#include<stdio.h>
#include<stdlib.h>
int main(){
	int i,n,lv;
	double luck,a;
	while(scanf("%d",&n)!=EOF){
		luck=0;
		lv=0;
		for(i=0;i<n;i++){
			scanf("%lf",&a);
			if(a>0)
				a=a*0.5;
			luck=luck+a;
			if(luck<0)
				lv++;
		}
		printf("%d\n",lv);
	}
	return 0;
}