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

#define ll long long
#define mp make_pair
#define pb push_back

int main() {
    int x; cin >> x;
    for (int i=0; i<x; i++) {
        int y; cin >> y;
        vector<ll> neg;
        vector<ll> zero;
        vector<ll> pos;
        ll p = 1;
        ll q = 1;
        for (int j=0; j<y; j++) {
            ll z; cin >> z;
            p *= z;
            if (z < 0) { neg.pb(z); q *= z;}
            else if (z == 0) { zero.pb(z); }
            else { pos.pb(z); q *= z;}
        }
        sort(neg.begin(), neg.end());
        sort(zero.begin(), zero.end());
        sort(pos.begin(), pos.end());
        if (pos.size() == 0 && zero.size() == 0 && neg.size() == 1) { cout << p << endl; }
        else if (pos.size() == 0 && neg.size() == 1 && zero.size() > 0) { cout << 0 << endl;}
        else if (pos.size() == 0 && neg.size() == 0) { cout << 0 << endl; }
        else if (neg.size() == 0) { cout << q << endl; }
        else { cout << max(q, q / neg[neg.size()-1]) << endl; }
    }
}