#include<iostream>

#include<algorithm>

#include<vector>

#include<cstring>

#include<cstdio>

#include<queue>

#include<cmath>

#include<stack>

#include<set>

#include<string>

using namespace std;

typedef long long LL;

#define MAXN 50001

#define INF 0x3f3f3f3f

int main()

{

    LL a[MAXN],n,m=INF,temp=;

    scanf("%lld",&n);

    for(LL i=;i<n;i++)

    {

        scanf("%lld",&a[i]);

        temp+=a[i];

        if(temp<)

            m = min(m,temp);

    }

    printf("%lld\n",-m);

    return ;

}