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

int main(void) {
    int N;
    cin >> N;
    int a;
    ll ans = 0;
    for (int i=0; i<N; i++) {
        cin >> a;
        if (a < 0) ans += -a;
        else {
            if (ans <= 0 || a <= 1) ans += a;
            else ans *= a;
        }
    }
    cout << ans << endl;
    return 0;
}