#include <iostream>
#include <algorithm>
#include <vector>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long; 
using mint = modint998244353;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using vmi = vector<mint>;
using vvmi = vector<vmi>;
using vvvmi = vector<vvmi>;
#define all(a) (a).begin(), (a).end()
#define rep2(i, m, n) for (int i = (m); i < (n); ++i)
#define rep(i, n) rep2(i, 0, n)
#define drep2(i, m, n) for (int i = (m)-1; i >= (n); --i)
#define drep(i, n) drep2(i, n, 0)


int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t; cin >> t;
    while(t--){
        int n; cin >> n;
        vll a(n); rep(i, n)cin >> a[i];
        sort(all(a));
        if(a[0] >= 0){
            cout << a[0]*a[n-1] << endl;
            continue;
        }
        if(a[n-1] < 0){
            cout << a[n-1]*a[0] << endl;
            continue;
        }
        int it = 0;
        while(a[it] < 0)it++;
        cout << a[it]*a[it-1] << endl;
    }
    return 0;
}