#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
using mint = modint998244353;
const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n) - 1; i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r) - 1;i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
void solve() {
	int n; cin >> n;
	vector<long long> a(n);
	rep(i, n)cin >> a[i];

	vector<long long> pl, mn;
	for (auto e : a) {
		if (e >= 0)pl.push_back(e);
		if (e <= 0)mn.push_back(e);
	}

	if (pl.size() == 0 || mn.size() == 0) {
		auto min_a = *min_element(a.begin(), a.end());
		auto max_a = *max_element(a.begin(), a.end());

		cout << min_a * max_a << endl;
	}
	else {
		auto min_plus = *min_element(pl.begin(), pl.end());
		auto max_minus = *max_element(mn.begin(), mn.end());
		cout << min_plus * max_minus << endl;
	}
}
int main() {
	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
	int t; cin >> t;
	while (t--) solve();
	return 0;
}