#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(x) (x).begin(),(x).end()
template<class T> ll MIN(const vector<T>&a) { return *min_element(all(a)); }
template<class T> ll MAX(const vector<T>&a) { return *max_element(all(a)); }
int main() {
	int tt;
	cin >> tt;
	while(tt--) {
		int N;
		cin >> N;
		vector<int>A(N);
		for(int i = 0; i < N; i++) cin >> A[i];
		vector<int>POS,NEG;
		bool f = false;
		for(int i = 0; i < N; i++) {
			if(A[i]==0)f=1;
			else if(A[i]<0)NEG.push_back(A[i]);
			else POS.push_back(A[i]);
		}
		vector<ll>th;
		if(f)th.push_back(0);
		if(NEG.size()&&POS.size())th.push_back(MIN(POS)*MAX(NEG));
		if(POS.size()>=2) th.push_back(MIN(POS)*MAX(POS));
		if(NEG.size()>=2) th.push_back(MIN(NEG)*MAX(NEG));
		assert(!th.empty());
		cout<<MIN(th)<<"\n";
	}
}