T = int(input())
for _ in range(T):
    N = int(input())
    if(N.bit_count() == 1):
        print(-1)
        continue
    
    one = []
    for i in range(1000):
        if(1<<i & N == 0):continue
        one.append(i)
        if(len(one) == 2):break
    
    print(sum([1<<i for i in range(one[0],one[1])]))