#include<iostream>
#include<algorithm>
using namespace std;
int main(){
    int t; cin >> t;
    while(t--){
        int n; cin >> n;
        int a[n], i;
        for(i = 0; i < n; i++){
            cin >> a[i];
        }
        sort(a, a+n);
        cout << (a[(n-1)]) * (a[(n-2)]) << endl;
    }
}