#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using ii = pair<int, int>;
using iii = tuple<int, int, int>;

#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple

int n;
ll ans, p;

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n;
	for (int i = 1, a; i <= n; i++) {
		cin >> a;
		p += a;
		if (i > 1 && p > 0) {
			ans += p;
		}
	}
	cout << ans << '\n';
}