MOD = 998244353

def solve():
    N, K = map(int, input().split())

    ans = 1
    
    # Iterate for up to 61 bits (s from 0 to 60)
    # This range is sufficient since N, K <= 10^18 < 2^60.
    # Higher bits of N and K will be 0.
    for s in range(61): 
        n_bit = (N >> s) & 1
        k_bit = (K >> s) & 1

        factor = 0
        if n_bit == 0 and k_bit == 0:
            factor = 1
        elif n_bit == 0 and k_bit == 1:
            factor = 2
        elif n_bit == 1 and k_bit == 0:
            factor = 3
        elif n_bit == 1 and k_bit == 1: # (n_bit == 1 and k_bit == 1)
            factor = 4
        
        ans = (ans * factor) % MOD
        
    print(ans)

solve()