#include <bits/stdc++.h>

using namespace std;

int main() {
    int i, month, left = 0, save = 0, sum, plan, flag = 0;
    for (month = 1; month <= 12; month++) {
        left += 300;
        scanf("%d", &plan);
        left = left - plan;
        if (left < 0) {
            flag = 1;
            break;
        } else {
            i = left / 100;
            save += (100 * i);
            left -= (100 * i);
        }
    }
    if (flag > 0)
        printf("-%d", month);
    else {
        sum = ((1.2 * save) + left);
        printf("%d", sum);
    }
    return 0;
}