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