T = int(input())
for i in range(T):
  N = int(input())
  C = -1
  D = -1
  for j in range(31):
    if(N & (1<<j)):
      if C == -1:
        C = j
      elif D == -1:
        D = j
  if(D == -1):
    print(-1)
  else:
    print((1<<D) - (1<<C))