#include <iostream>
#include <math.h>
#define ll long long int
using namespace std;

int main() {
	ll n, day_profit, max_lend = 0;
	ll sum = 0;
	cin >> n;
	ll n_copy = n;
	while (n_copy--) {
		cin >> day_profit;
		sum += day_profit;
		if (sum < 0 && (abs(sum) + 1 > max_lend))
			max_lend = abs(sum) + 1;
	}
	cout << max_lend;
	}