include <bits/stdc++.h>

using namespace std; const int N = 666666; int n, a[N]; bool check(int x) { int cur = x; for (int i = 0; i < n; i++) {

cur += a[i];
if (cur <= 0)
	return false;

} return true; } int main() { cin >> n; for (int i = 0; i < n; i++)

cin >> a[i];

int l = 1, r = 1e9; while (l < r) {

int mid = (l + r) >> 1;
if (check(mid))
	r = mid;
else
	l = mid + 1;

} cout << l << endl; return 0; }