#include<stdio.h>

int main(){
	int n;
	double a;
	int count = 0;
	double xy = 0;
	while(scanf("%d",&n) != EOF){
		int count =  0 ;
		double xy = 0;
	   for(int i = 0;i < n;i++){
		scanf("%lf",&a);
		if(a < 0){
			xy = xy + a;
		//	printf("%.f\n",xy);
		}
		else if(a >= 0){
			xy = xy + a/2.00; 
		//	printf("%.f\n",xy);
		}
		if(xy < 0){
			count ++;
		}
	}
		printf("%d\n",count);
	}

	return 0;
}