#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define ll long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define repl(i,a,b) for(ll i=(a);i<(b);i++)
#define all(a) (a).begin(),(a).end()

template <typename T> bool chmin(T &a,T b){if(a>b){a=b;return true;} return false;}
template <typename T> bool chmax(T &a,T b){if(a<b){a=b;return true;} return false;}


int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  int T; cin >> T;
  while(T--){
    int n; cin >> n;
    vector<ll> a(n);
    bool plus=false,minus=false,ex0=false;
    rep(i,0,n){
      cin >> a[i];
      if(a[i]>0) plus=true;
      if(a[i]<0) minus=true;
      if(a[i] == 0) ex0=true;
    }
    if(plus && minus){
      ll x=1e18,y=-1e18;
      rep(i,0,n){
        if(a[i]>0) chmin(x,a[i]);
        else if(a[i]<0) chmax(y,a[i]);
      }
      if(ex0) cout << "0\n";
      else cout << x*y << '\n';
    }
    else if(plus){
      sort(all(a));
      cout << a[0]*a[1] << '\n';
    }
    else{
      sort(a.rbegin(),a.rend());
      cout << a[0]*a[1] << '\n';
    }
  }
}