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