#include <bits/stdc++.h>
using namespace std;
int main()
{
	int rest = 0;
	int cun = 0;
	int cun2 = 0;
	for (int i = 1; i <= 12; i++){
		int cost; cin >> cost;
		rest = 300 + rest;
		if (rest < cost){
			cout << -i;
			return 0;
		}
		rest = rest - cost;
		if (rest >= 100){
			
			cun = rest / 100 * 100;
			rest = rest - cun;
		} 
		cun2 = cun + cun2;
 	} 
 	cout << cun2 * 1.2 + rest;
}