#include <iostream>
using namespace std;
#include <math.h>
int main (){
    int n;
    cin>>n;
    int arr[n];
    for (int i=0;i<n;i++){
        cin>>arr[i];
    }
    int pre[n] ={0};
    for (int i=0;i<n;i++){
        if (i==0) pre[i] = arr[i];
        else pre[i]+=(pre[i-1]+arr[i]);
    }
    int min =pre[0];
    for (int i=0;i<n;i++) if (pre[i]<min) min = pre[i];
    if (min>0) cout <<0<<endl;
    else {
        if (min==0) cout <<min+1<<endl;
        else {
            min = abs(min) +1;
            cout <<min<<endl;
        }
    }
    
    return 0;
}