A,B = map(int,input().split())
bitA = bin(A)[2:].zfill(31)
bitB = bin(B)[2:].zfill(31)

if A & B != A:
    print(0)
    exit()
count = 1
for i in range(len(bitA)):
    if bitA[i] != bitB[i]:
        count *= 2
print(max(1,count//2))