R=range
I=input
for t in R(int(I())):
	N=int(I());x,l=0,31
	for d in R(31):
		if(N>>d&1)<1and d>l+1:break
		elif((N>>d)&1)^(d>l):l=d;x|=1<<d
	else:x=-1
	print(x)