#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    vector<ll> a(n);
    rep(i, n) cin >> a[i];
    sort(a.begin(), a.end());
    if (a.front() >= 0 || a.back() <= 0) {
      cout << a.front() * a.back() << '\n';
    }
    else {
      auto it1 = lower_bound(a.begin(), a.end(), 0LL);
      assert(it1 != a.begin());
      auto it2 = prev(it1);
      cout << *it1 * *it2 << '\n';
    }
  }
  return 0;
}