#include <bits/stdc++.h>

using namespace std;
ifstream in("produs4.in");
ofstream out("produs4.out");
const int NMAX = 30001;
long long v[NMAX];
int main()
{
    int t, n;
    in >> t;
    while( t-- ){
        in >> n;
        for( int i = 0 ; i < n ; i++ )
            in >> v[i];
        if( n == 3 )
            out << v[0] * v[1] * v[2];
        else{
            sort(v, v+n);
            long long p1 = v[0]*v[1]*v[n-1];
            long long p2 = v[n-1]*v[n-2]*v[n-3];
            out << max(p1, p2);
        }
        out << endl;
    }
    return 0;
}