from sys import stdin
R=range
I=input
def P(n):return sum(n>>d&1 for d in R(31))
for t in R(int(I())):
	N=int(stdin.readline());p,y,a=P(N),N,-1
	for d in R(31):
		if y>>d&1:
			y+=1<<d
			if p>P(y):a=y-N;break
	print(a if p>1 else -1)