#include<stdio.h>
int main(){
	int n;
	int b;
	double a,t=0;
	while(scanf("%d",&n)!=EOF){
		b=0;t=0;
		while(n--){
			scanf("%lf",&a);
				if(a>0)
				{
					a=a/2;
					t=a+t;
				}
				else t=a+t;
				if(t<0)
				{
					b=b+1;
				}
				else b=b;
			}
			printf("%d\n",b);
		}
	return 0;
}