#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
const int N = 2000010, MOD = 998244353, INF = 0x3f3f3f3f;
int n, m, w[N];


void solve() {
    sort(w + 1, w + n + 1);
    if (w[1] >= 0 || w[n] <= 0) {
        printf("%lld\n", (ll)w[1] * w[n]);
    } else {
        for (int i = 2; i < n + 1; i++)
            if (w[i] >= 0 && w[i - 1] <= 0) {
                printf("%lld\n", w[i] * (ll)w[i - 1]);
                return;
            }
    }
}

int main() {
    int T;
    scanf("%d", &T);
    while (T--) {
        scanf("%d", &n);
        for (int i = 1; i < n + 1; i++) scanf("%d", w + i);
        solve();
    }
    return 0;
}