Mã chấm: 267876

Main.cc: In function ‘int main()’:
Main.cc:9:5: error: ‘cin’ was not declared in this scope
     cin >> A >> B >> X >> Y;
     ^~~
Main.cc:9:5: note: suggested alternative: ‘sin’
     cin >> A >> B >> X >> Y;
     ^~~
     sin
Main.cc:13:5: error: ‘cout’ was not declared in this scope
     cout << tongtien;
     ^~~~
Main.cc:13:5: note: suggested alternative: ‘cosl’
     cout << tongtien;
     ^~~~
     cosl