import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################
"""

a[i] = 0 があったら X >= 0
逆に 0 で

a[i] < 0 と a[i] > 0 があったら X < 0

a[i] < 0 だけのときは max(a) とつなげる

a[i] > 0 だけの時は min(a) とつなげる

"""
def solve(n, a):
    if 0 in a:
        return 0
    
    if all(x > 0 for x in a) or all(x < 0 for x in a):
        return min(a) * max(a)

    A = [x for x in a if x > 0]
    B = [-x for x in a if x < 0]
    # print(A, B)
    
    return - min(A) * min(B)

for _ in range(ni()):
    n = ni()
    a = na()
    print(solve(n, a))