#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll,ll> P;
#define REP(i,n) for(ll i=0;i<ll(n);i++)











int main(void){
	cin.tie(nullptr);  ios_base::sync_with_stdio(false);
	ll i,j;





	int T;
	cin >> T;
	while(T--){


		ll n;
		cin >> n;

		vector<ll> a(n);
		REP(i,n) cin >> a[i];


		sort(a.begin(),a.end());

		if(a[0]>=0){
			cout << a[0]*a[n-1] << endl;
		}
		else if(a[0]<0 && a[n-1]<=0){
			cout << a[0]*a[n-1] << endl;
		}
		else if(a[0]<0 && a[n-1]>0){
			REP(i,n){
				if(a[i]>0){
					cout << a[i-1]*a[i] << endl;
					break;
				}
			}
		}




	}







	return 0;

}