import sys
input=lambda: sys.stdin.readline().rstrip()
a,b=map(int,input().split())
ct01,ct10=0,0
for i in range(31):
  aa,bb=a&(1<<i),b&(1<<i)
  if (not aa) and bb:
    ct01+=1
  if aa and (not bb):
    ct10+=1
if ct10:
  print(0)
else:
  print(2**(max(0,ct01-1)))