def popcount(n):
    return bin(n).count("1")

def not32(n):
    return n ^ 0xffffffff

A, B = map(int, input().split())
ans = 0
if A & B == A:
    pc = popcount(not32(A) & B)
    ans = 1 if pc == 0 else (2**pc) // 2
print(ans)