A, B = map(int, input().split())

k = 1
n = 0
for i in range(32):
    if k & A > 0:
        if k & B == 0:
            n = -1
            break
    else:
        if k & B > 0:
            n += 1
    k <<= 1

if n == -1:
    print(0)
elif n == 0:
    print(1)
else:
    print(2 ** (n - 1))