import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]

def main():
    a, b = MI()
    dp = [[0] * 2 for _ in range(32)]
    dp[0][0] = 1
    for i in range(31):
        ak = a >> (30 - i) & 1
        bk = b >> (30 - i) & 1
        if ak==1 and bk==0:
            print(0)
            exit()
        if ak==1 or bk==0:
            dp[i+1]=dp[i]
            continue
        dp[i+1][1]=dp[i][0]+dp[i][1]*2
    #print(dp)
    print(sum(dp[31]))


main()