A,B=map(int, input().split())
cnt=1
for i in range(32):
    if (A>>i)&1==1 and (B>>i)&1==1: # (1,1)
        cnt*=1
    if (A>>i)&1==0 and (B>>i)&1==1: # (1,0),(0,1)
        cnt*=2
    if (A>>i)&1==1 and (B>>i)&1==0: #
        cnt*=0
    if (A>>i)&1==0 and (B>>i)&1==0: # (0,0)
        cnt*=1
print((cnt-1)//2+1)