def solve():
  n = int(input())
  ni = n
  pc = 0
  x = 0
  for i in range(31):
    if ni%2 == 1:
      pc += 1
      if pc == 1:
        x += 2**i
    else:
      if pc == 1:
        x += 2**i
      elif pc > 1:
        break
    ni //= 2
  else:
    return -1
  return x

t = int(input())
for i in range(t):
  print(solve())