#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
const long long mod=998244353;
const long long mod2=567629137;
void solve(){
    int N;
    cin>>N;
    ll A[N+1];
    for(int i=1;i<=N;i++) cin>>A[i];
    vector<ll>plus,minus;
    int zero=0;
    for(int i=1;i<=N;i++){
        if(A[i]>0) plus.push_back(A[i]);
        else if(A[i]<0) minus.push_back(A[i]);
        else zero++;
    }
    sort(plus.begin(),plus.end());
    sort(minus.rbegin(),minus.rend());

    if(zero==0){
        ll ans=2e18;
        if(plus.size()>=1) ans=min(ans,plus[0]*plus[plus.size()-1]);
        if(minus.size()>=1) ans=min(ans,minus[0]*minus[minus.size()-1]);
        if(plus.size()>=1 && minus.size()>=1){
            ans=min(ans,plus[0]*minus[0]);
        }
        cout<<ans<<endl;
    }
    else{
        cout<<0<<endl;
    }
}
int main(){
    cin.tie(0)->sync_with_stdio(0);
    cout.tie(0);
    int T;
    cin>>T;
    while(T--) solve();
}