# gemini
MOD = 998244353


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

    # K = 2^N - 1, L = 2^{N-1} - 1
    K = (pow(2, N, MOD) - 1) % MOD
    L = (pow(2, N-1, MOD) - 1) % MOD

    # nCr を分子と分母で計算
    def nCr_large_n(n, r):
        if r < 0 or r > n:
            return 0  # ただし今回は n が非常に大きいので n < r の判定に注意
        num = 1
        den = 1
        for i in range(r):
            num = num * (n - i) % MOD
            den = den * (i + 1) % MOD
        return num * pow(den, MOD - 2, MOD) % MOD

    ans1 = nCr_large_n(K, M)
    ans2 = K * nCr_large_n(L, M - 1) % MOD

    print((ans1 - ans2) % MOD)


solve()