#include <iostream>
#include <vector>
#include <algorithm>
#include <set>

using namespace std;

void solve()
{
  int n;
  cin >> n;
  vector<long long> a(n);
  for (int i = 0; i < n; ++i) cin >> a[i];
  sort(a.begin(), a.end());
  long long ans = 1e18;
  for (int i = 1; i < n - 1; ++i)
  {
    long long val = a[i];
    long long tmp = max(val * a[0], val * a[n - 1]);
    ans = min(ans, tmp);
  }
  for (int i = 0; i < n - 1; ++i)
  {
    if (a[i] < 0 && a[i + 1] >= 0)
    {
      ans = min(ans, a[i] * a[i + 1]);
    }
  }
  ans = min(ans, max(a[0] * a[1], a[0] * a[n - 1]));
  ans = min(ans, max(a[n - 1] * a[n - 2], a[0] * a[n - 1]));
  cout << ans << endl;
}

int main()
{
  int t;
  cin >> t;
  while (t--) solve();
}