include <bits/stdc++.h>

using namespace std;

int main() {

int n;
cin >> n;
vector<double> a(n);
for (int i = 0; i < n; i++) cin >> a[i];

double t = 0;
double r = 0;
double s = 0;
int d = 0;

for (int i = 0; i < n; i++) {
    t += a[i];
    s += a[i];
    d++;

   
    if (d == 5) {
        r += s * 1.1;
        s = 0;
        d = 0;
    }
}

double l = r - t;
long long k = floor(l); 

cout << k;
return 0;

}