#include<bits/stdc++.h>

using namespace std;

long long n,a[9000000];

bool check(long long x)
{
	for(int i = 0;i <= n;i++) x += a[i];
	
	if(x > 0)return true;
	else return false;
}

long long f(long long l,long long r)
{
	while(l <= r)
	{
		long long mid = (l + r) / 2;
		if(check(mid)) r = mid - 1;
		else l = mid + 1;
	}
	return l;
}

int main()
{
	
	cin>>n;
	
	for(int i = 1;i <= n;i++)cin>>a[i];
	
	cout<<f(1,9000000000000ll);

    return 0;
}