MOD = 998244353

def main():
    N, K = map(int, input().split())
    result = 1
    for d in range(60):
        k_bit = (K >> d) & 1
        n_bit = (N >> d) & 1
        if k_bit == 0:
            if n_bit == 1:
                result = result * 3 % MOD
        else:
            if n_bit == 0:
                result = result * 2 % MOD
            else:
                result = result * 4 % MOD
    print(result % MOD)

if __name__ == "__main__":
    main()