t = int(input())
while t:
n = int(input())
factors = [int(x) for x in input().split()]
for x in range(-100,101):
sum = 0
copyX = 1
for factor in factors:
sum += copyX*factor
copyX = copyX * x
if sum == 0:
print(x % 32768)
break
t -= 1
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