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    <p class="text-center">
        <b>
            Mã chấm:
            <a href="https://itcoder.hutech.edu.vn/solution/detail?id=13633">13633</a>        </b>
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                        <pre>Main.cc: In function ‘int main()’:
Main.cc:7:9: error: no match for ‘operator&lt;&lt;’ (operand types are ‘std::istream {aka std::basic_istream}’ and ‘int’)
     cin &lt;
Main.cc:7:9: note:   no known conversion for argument 1 from ‘std::istream {aka std::basic_istream}’ to ‘int’
In file included from /usr/include/c++/7/string:52:0,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from Main.cc:2:
/usr/include/c++/7/bits/basic_string.h:6284:5: note: candidate: template std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, const std::__cxx11::basic_string&lt;_CharT, _Traits, _Alloc&gt;&amp;)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __os,
     ^~~~~~~~
/usr/include/c++/7/bits/basic_string.h:6284:5: note:   template argument deduction/substitution failed:
Main.cc:7:11: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
     cin &lt; std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, const std::error_code&amp;)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __os, const error_code&amp; __e)
     ^~~~~~~~
/usr/include/c++/7/system_error:217:5: note:   template argument deduction/substitution failed:
Main.cc:7:11: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
     cin &lt; std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, _CharT)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, _CharT __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:497:5: note:   template argument deduction/substitution failed:
Main.cc:7:11: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
     cin &lt; std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, char)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:502:5: note:   template argument deduction/substitution failed:
Main.cc:7:11: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
     cin &lt; std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, char)
     operator&lt;&lt;(basic_ostream&amp; __out, char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:508:5: note:   template argument deduction/substitution failed:
Main.cc:7:11: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
     cin &lt; std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, signed char)
     operator&lt;&lt;(basic_ostream&amp; __out, signed char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:514:5: note:   template argument deduction/substitution failed:
Main.cc:7:11: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
     cin &lt; std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, unsigned char)
     operator&lt;&lt;(basic_ostream&amp; __out, unsigned char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:519:5: note:   template argument deduction/substitution failed:
Main.cc:7:11: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
     cin &lt; std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, const _CharT*)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, const _CharT* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:539:5: note:   template argument deduction/substitution failed:
Main.cc:7:11: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
     cin &lt; std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, const char*)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, const char* __s)
     ^~~~~~~~
/usr/include/c++/7/bits/ostream.tcc:321:5: note:   template argument deduction/substitution failed:
Main.cc:7:11: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
     cin &lt; std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, const char*)
     operator&lt;&lt;(basic_ostream&amp; __out, const char* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:556:5: note:   template argument deduction/substitution failed:
Main.cc:7:11: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
     cin &lt; std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, const signed char*)
     operator&lt;&lt;(basic_ostream&amp; __out, const signed char* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:569:5: note:   template argument deduction/substitution failed:
Main.cc:7:11: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
     cin &lt; std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, const unsigned char*)
     operator&lt;&lt;(basic_ostream&amp; __out, const unsigned char* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:574:5: note:   template argument deduction/substitution failed:
Main.cc:7:11: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
     cin &lt; typename std::enable_if &gt;, std::__is_convertible_to_basic_ostream&lt;_Ostream&gt;, std::__is_insertable::__ostream_type, const _Tp&amp;, void&gt; &gt;::value, typename std::__is_convertible_to_basic_ostream&lt;_Tp&gt;::__ostream_type&gt;::type std::operator&lt;&lt;(_Ostream&amp;&amp;, const _Tp&amp;)
     operator&lt;&lt;(_Ostream&amp;&amp; __os, const _Tp&amp; __x)
     ^~~~~~~~
/usr/include/c++/7/ostream:682:5: note:   template argument deduction/substitution failed:
/usr/include/c++/7/ostream: In substitution of ‘template typename std::enable_if &gt;, std::__is_convertible_to_basic_ostream&lt;_Ostream&gt;, std::__is_insertable::__ostream_type, const _Tp&amp;, void&gt; &gt;::value, typename std::__is_convertible_to_basic_ostream&lt;_Tp&gt;::__ostream_type&gt;::type std::operator&lt;&lt;(_Ostream&amp;&amp;, const _Tp&amp;) [with _Ostream = std::basic_istream&amp;; _Tp = int]’:
Main.cc:7:11:   required from here
/usr/include/c++/7/ostream:682:5: error: no type named ‘type’ in ‘struct std::enable_if’
Main.cc:10:13: error: no match for ‘operator&lt;&lt;’ (operand types are ‘std::istream {aka std::basic_istream}’ and ‘int’)
         cin &lt;&lt; l;
         ~~~~^~~~
Main.cc:10:13: note: candidate: operator&lt;&lt;(int, int) 
Main.cc:10:13: note:   no known conversion for argument 1 from ‘std::istream {aka std::basic_istream}’ to ‘int’
In file included from /usr/include/c++/7/string:52:0,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from Main.cc:2:
/usr/include/c++/7/bits/basic_string.h:6284:5: note: candidate: template std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, const std::__cxx11::basic_string&lt;_CharT, _Traits, _Alloc&gt;&amp;)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __os,
     ^~~~~~~~
/usr/include/c++/7/bits/basic_string.h:6284:5: note:   template argument deduction/substitution failed:
Main.cc:10:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
         cin &lt;&lt; l;
                ^
In file included from /usr/include/c++/7/bits/ios_base.h:46:0,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from Main.cc:2:
/usr/include/c++/7/system_error:217:5: note: candidate: template std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, const std::error_code&amp;)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __os, const error_code&amp; __e)
     ^~~~~~~~
/usr/include/c++/7/system_error:217:5: note:   template argument deduction/substitution failed:
Main.cc:10:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
         cin &lt;&lt; l;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:497:5: note: candidate: template std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, _CharT)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, _CharT __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:497:5: note:   template argument deduction/substitution failed:
Main.cc:10:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
         cin &lt;&lt; l;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:502:5: note: candidate: template std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, char)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:502:5: note:   template argument deduction/substitution failed:
Main.cc:10:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
         cin &lt;&lt; l;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:508:5: note: candidate: template std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, char)
     operator&lt;&lt;(basic_ostream&amp; __out, char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:508:5: note:   template argument deduction/substitution failed:
Main.cc:10:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
         cin &lt;&lt; l;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:514:5: note: candidate: template std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, signed char)
     operator&lt;&lt;(basic_ostream&amp; __out, signed char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:514:5: note:   template argument deduction/substitution failed:
Main.cc:10:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
         cin &lt;&lt; l;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:519:5: note: candidate: template std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, unsigned char)
     operator&lt;&lt;(basic_ostream&amp; __out, unsigned char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:519:5: note:   template argument deduction/substitution failed:
Main.cc:10:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
         cin &lt;&lt; l;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:539:5: note: candidate: template std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, const _CharT*)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, const _CharT* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:539:5: note:   template argument deduction/substitution failed:
Main.cc:10:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
         cin &lt;&lt; l;
                ^
In file included from /usr/include/c++/7/ostream:693:0,
                 from /usr/include/c++/7/iostream:39,
                 from Main.cc:2:
/usr/include/c++/7/bits/ostream.tcc:321:5: note: candidate: template std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, const char*)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, const char* __s)
     ^~~~~~~~
/usr/include/c++/7/bits/ostream.tcc:321:5: note:   template argument deduction/substitution failed:
Main.cc:10:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
         cin &lt;&lt; l;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:556:5: note: candidate: template std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, const char*)
     operator&lt;&lt;(basic_ostream&amp; __out, const char* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:556:5: note:   template argument deduction/substitution failed:
Main.cc:10:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
         cin &lt;&lt; l;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:569:5: note: candidate: template std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, const signed char*)
     operator&lt;&lt;(basic_ostream&amp; __out, const signed char* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:569:5: note:   template argument deduction/substitution failed:
Main.cc:10:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
         cin &lt;&lt; l;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:574:5: note: candidate: template std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, const unsigned char*)
     operator&lt;&lt;(basic_ostream&amp; __out, const unsigned char* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:574:5: note:   template argument deduction/substitution failed:
Main.cc:10:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
         cin &lt;&lt; l;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:682:5: note: candidate: template typename std::enable_if &gt;, std::__is_convertible_to_basic_ostream&lt;_Ostream&gt;, std::__is_insertable::__ostream_type, const _Tp&amp;, void&gt; &gt;::value, typename std::__is_convertible_to_basic_ostream&lt;_Tp&gt;::__ostream_type&gt;::type std::operator&lt;&lt;(_Ostream&amp;&amp;, const _Tp&amp;)
     operator&lt;&lt;(_Ostream&amp;&amp; __os, const _Tp&amp; __x)
     ^~~~~~~~
/usr/include/c++/7/ostream:682:5: note:   template argument deduction/substitution failed:
/usr/include/c++/7/ostream: In substitution of ‘template typename std::enable_if &gt;, std::__is_convertible_to_basic_ostream&lt;_Ostream&gt;, std::__is_insertable::__ostream_type, const _Tp&amp;, void&gt; &gt;::value, typename std::__is_convertible_to_basic_ostream&lt;_Tp&gt;::__ostream_type&gt;::type std::operator&lt;&lt;(_Ostream&amp;&amp;, const _Tp&amp;) [with _Ostream = std::basic_istream&amp;; _Tp = int]’:
Main.cc:10:16:   required from here
/usr/include/c++/7/ostream:682:5: error: no type named ‘type’ in ‘struct std::enable_if’
Main.cc:11:13: error: no match for ‘operator&lt;&lt;’ (operand types are ‘std::istream {aka std::basic_istream}’ and ‘int’)
         cin &lt;&lt; r;
         ~~~~^~~~
Main.cc:11:13: note: candidate: operator&lt;&lt;(int, int) 
Main.cc:11:13: note:   no known conversion for argument 1 from ‘std::istream {aka std::basic_istream}’ to ‘int’
In file included from /usr/include/c++/7/string:52:0,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from Main.cc:2:
/usr/include/c++/7/bits/basic_string.h:6284:5: note: candidate: template std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, const std::__cxx11::basic_string&lt;_CharT, _Traits, _Alloc&gt;&amp;)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __os,
     ^~~~~~~~
/usr/include/c++/7/bits/basic_string.h:6284:5: note:   template argument deduction/substitution failed:
Main.cc:11:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
         cin &lt;&lt; r;
                ^
In file included from /usr/include/c++/7/bits/ios_base.h:46:0,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from Main.cc:2:
/usr/include/c++/7/system_error:217:5: note: candidate: template std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, const std::error_code&amp;)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __os, const error_code&amp; __e)
     ^~~~~~~~
/usr/include/c++/7/system_error:217:5: note:   template argument deduction/substitution failed:
Main.cc:11:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
         cin &lt;&lt; r;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:497:5: note: candidate: template std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, _CharT)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, _CharT __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:497:5: note:   template argument deduction/substitution failed:
Main.cc:11:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
         cin &lt;&lt; r;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:502:5: note: candidate: template std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, char)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:502:5: note:   template argument deduction/substitution failed:
Main.cc:11:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
         cin &lt;&lt; r;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:508:5: note: candidate: template std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, char)
     operator&lt;&lt;(basic_ostream&amp; __out, char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:508:5: note:   template argument deduction/substitution failed:
Main.cc:11:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
         cin &lt;&lt; r;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:514:5: note: candidate: template std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, signed char)
     operator&lt;&lt;(basic_ostream&amp; __out, signed char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:514:5: note:   template argument deduction/substitution failed:
Main.cc:11:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
         cin &lt;&lt; r;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:519:5: note: candidate: template std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, unsigned char)
     operator&lt;&lt;(basic_ostream&amp; __out, unsigned char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:519:5: note:   template argument deduction/substitution failed:
Main.cc:11:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
         cin &lt;&lt; r;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:539:5: note: candidate: template std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, const _CharT*)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, const _CharT* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:539:5: note:   template argument deduction/substitution failed:
Main.cc:11:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
         cin &lt;&lt; r;
                ^
In file included from /usr/include/c++/7/ostream:693:0,
                 from /usr/include/c++/7/iostream:39,
                 from Main.cc:2:
/usr/include/c++/7/bits/ostream.tcc:321:5: note: candidate: template std::basic_ostream&lt;_CharT, _Traits&gt;&amp; std::operator&lt;&lt;(std::basic_ostream&lt;_CharT, _Traits&gt;&amp;, const char*)
     operator&lt;&lt;(basic_ostream&lt;_CharT, _Traits&gt;&amp; __out, const char* __s)
     ^~~~~~~~
/usr/include/c++/7/bits/ostream.tcc:321:5: note:   template argument deduction/substitution failed:
Main.cc:11:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream&lt;_CharT, _Traits&gt;’
         cin &lt;&lt; r;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:556:5: note: candidate: template std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, const char*)
     operator&lt;&lt;(basic_ostream&amp; __out, const char* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:556:5: note:   template argument deduction/substitution failed:
Main.cc:11:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
         cin &lt;&lt; r;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:569:5: note: candidate: template std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, const signed char*)
     operator&lt;&lt;(basic_ostream&amp; __out, const signed char* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:569:5: note:   template argument deduction/substitution failed:
Main.cc:11:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
         cin &lt;&lt; r;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:574:5: note: candidate: template std::basic_ostream&amp; std::operator&lt;&lt;(std::basic_ostream&amp;, const unsigned char*)
     operator&lt;&lt;(basic_ostream&amp; __out, const unsigned char* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:574:5: note:   template argument deduction/substitution failed:
Main.cc:11:16: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
         cin &lt;&lt; r;
                ^
In file included from /usr/include/c++/7/iostream:39:0,
                 from Main.cc:2:
/usr/include/c++/7/ostream:682:5: note: candidate: template typename std::enable_if &gt;, std::__is_convertible_to_basic_ostream&lt;_Ostream&gt;, std::__is_insertable::__ostream_type, const _Tp&amp;, void&gt; &gt;::value, typename std::__is_convertible_to_basic_ostream&lt;_Tp&gt;::__ostream_type&gt;::type std::operator&lt;&lt;(_Ostream&amp;&amp;, const _Tp&amp;)
     operator&lt;&lt;(_Ostream&amp;&amp; __os, const _Tp&amp; __x)
     ^~~~~~~~
/usr/include/c++/7/ostream:682:5: note:   template argument deduction/substitution failed:
/usr/include/c++/7/ostream: In substitution of ‘template typename std::enable_if &gt;, std::__is_convertible_to_basic_ostream&lt;_Ostream&gt;, std::__is_insertable::__ostream_type, const _Tp&amp;, void&gt; &gt;::value, typename std::__is_convertible_to_basic_ostream&lt;_Tp&gt;::__ostream_type&gt;::type std::operator&lt;&lt;(_Ostream&amp;&amp;, const _Tp&amp;) [with _Ostream = std::basic_istream&amp;; _Tp = int]’:
Main.cc:11:16:   required from here
/usr/include/c++/7/ostream:682:5: error: no type named ‘type’ in ‘struct std::enable_if’
Main.cc:15:19: error: expected ‘)’ before ‘mod’
             if (j mod 4==0) dem++;
                   ^~~
Main.cc:17:22: error: expected ‘)’ before ‘mod’
                 if(j mod 7==0) dem++;
                      ^~~
Main.cc:19:26: error: expected ‘)’ before ‘mod’
                     if(j mod 11==0) dem++;
                          ^~~
Main.cc:21:14: error: no match for ‘operator&gt;&gt;’ (operand types are ‘std::ostream {aka std::basic_ostream}’ and ‘int’)
         cout &gt;&gt; dem&gt;&gt;"\n";
         ~~~~~^~~~~~
Main.cc:21:14: note: candidate: operator&gt;&gt;(int, int) 
Main.cc:21:14: note:   no known conversion for argument 1 from ‘std::ostream {aka std::basic_ostream}’ to ‘int’
In file included from /usr/include/c++/7/string:53:0,
</pre>
            </div>

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</script>