#include<cstdio>
#include<cmath>
#include<algorithm>
#include<cstring>
#include<string>
#include<iostream>
#include<map>
#include<vector>
#include<set>
#include<queue>
using namespace std;

int n, ans;

int main()
{
	while (scanf("%d", &n)!=EOF)
	{
		double tmp, sum = 0;
		ans = 0;
		for (int i = 1; i <= n; i++)
		{
			scanf("%lf", &tmp);
			if (tmp > 0)
			{
				tmp /= 2;
			}
			sum += tmp;
			if (sum < 0)
			{
				ans++;
			}
		}
		printf("%d\n", ans);
	}
	return 0;
}