...

#include <iostream>
using namespace std;
int cnt = 0;
double s = 0;
int nm = 0;
int main(){
for (int i = 0;i<12;i++){
cnt -= 1;
int mu;
cin >> mu;
nm += 300;
if (nm < mu){
cout << cnt;
return 0;
}
nm -= mu;
int t = (nm / 100) * 100;
nm -= t;
s += t;
}
cout << s * 1.2 + nm;
}