MOD = 998244353

def main():
    import sys
    N, K = map(int, sys.stdin.readline().split())
    
    if (N & K) != 0:
        a = bin(N).count('1')
        b = bin(K).count('1')
        ans = pow(2, a + b, MOD)
    else:
        a = bin(N).count('1')
        b = bin(K).count('1')
        ans = pow(3, a, MOD) * pow(2, b, MOD) % MOD
    
    print(ans)

if __name__ == "__main__":
    main()