import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int t = Integer.parseInt(br.readLine());
		PrintWriter pw = new PrintWriter(System.out);
		for (int z = 0; z < t; z++) {
			int n = Integer.parseInt(br.readLine());
			String[] sa = br.readLine().split(" ");
			int[] a = new int[n];
			for (int i = 0; i < n; i++) {
				a[i] = Integer.parseInt(sa[i]);
			}

			List<Integer> m = new ArrayList<>();
			List<Integer> p = new ArrayList<>();
			boolean flg = false;
			for (int i = 0; i < n; i++) {
				if (a[i] == 0) {
					flg = true;
				} else if (a[i] > 0) {
					p.add(a[i]);
				} else {
					m.add(a[i]);
				}
			}

			Collections.sort(p);
			Collections.sort(m, Collections.reverseOrder());

			if (p.isEmpty()) {
				if (flg) {
					pw.println(0);
				} else {
					long v1 = m.get(0);
					long v2 = m.get(1);
					pw.println(v1 * v2);
				}
			} else {
				if (m.isEmpty()) {
					if (flg) {
						pw.println(0);
					} else {
						long v1 = p.get(0);
						long v2 = p.get(1);
						pw.println(v1 * v2);
					}
				} else {
					if (flg) {
						pw.println(0);
					} else {
						long v1 = m.get(0);
						long v2 = p.get(0);
						pw.println(v1 * v2);
					}
				}
			}
		}
		pw.flush();
		br.close();
	}
}