#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int tt;
  cin >> tt;
  while (tt--) {
    int n;
    cin >> n;
    VI a(n);
    rep(i, n) cin >> a[i];
    sort(all(a));
    if (a[0] < 0 && a[n-1] >= 0) {
      int i = 0;
      while (a[i] < 0) i++;
      cout << (ll)a[i-1] * a[i] << '\n';
      continue;
    }
    if (a[0] < 0) {
      for (int& x : a) x *= -1;
      sort(all(a));
    }
    cout << (ll)a[0] * a[n-1] << '\n';
  }
}