include <bits/stdc++.h>

using namespace std;

int n, a[100005];

void input() {

cin >> n;
for (int i = 1; i <= n; i++)
	cin >> a[i];

}

bool check(int x) {

int hp = x;

for (int i = 1; i == n; i++) {
	hp += a[i];
	if (hp < 1)
		return false;
}
return false;

}

void work() {

int l = 1, r = 1000, mid;
int ans = r;
while (l <= r) {
	mid = (l + r) / 2;
	if (check(mid)) {
		ans = min(ans, mid);
		r = mid - 1;
	}
}
cout << ans;

}

int main() {

input();
work();

return 0;

}