大神们帮忙看一下怎么改？

#include<iostream>
using namespace std;
int main() {
    int a[12], my = 0, mother = 0;
    for (int i = 1; i < 13; i++) {
        cin >> a[i];
    }
    for (int h=1; h < 13; h++) {      
        my += (300 - a[h]) % 100;
        mother += (300 - a[h]) / 100;
        if (my<0) {
            cout << "-" << h + 1 << endl;
        }
        }
    cout << my + (mother *120)<<endl;
    return 0;
}