#include<iostream>
#include<vector>
using namespace std;

typedef long long ll;

int main(){
    int n, x;
    cin >> n;

    ll a = 0, b = 0;
    for(int i = 0; i < n; i++){
        cin >> x;
        ll na = max(max(a, max(a*x, max(a+x, a-x))), max(b, max(b*x, max(b+x, b-x))));
        ll nb = min(min(a, min(a*x, min(a+x, a-x))), min(b, min(b*x, min(b+x, b-x))));
        a = na, b = nb;
    }

    cout << a << endl;

    return 0;
}