// 解説、見ました

#include <iostream>
#include <queue>
#include <vector>
#include <cmath>
#include <algorithm>
#include <map>

using namespace std;
using ll = long long;
const ll INF = 1e9;

int main() {
    int N;
    cin >> N;
    int a[N], cnt = 0, cnt1 = 0;
    for (int i = 0; i < N; i++) {
        cin >> a[i];
        if (a[i] < -1) cnt++;
        if (a[i] == -1) {
            cnt++; cnt1++;
        }
    }
    int ans = a[0];

    for (int i = 1; i < N; i++) {
        if (a[i] == 1 || a[i] == 0 || a[i] == -1) {
            ans += 1;
        } else {
            ans *= abs(a[i]);
            if (ans == 0) ans += abs(a[i]);
        }
    }

    cout << ans << endl;

    return 0;
}