MOD = 998244353

def solve():
    N, M = map(int, input().split())
    max_m = min(N + 1, M + 1)
    max_m = min(max_m, N + 1)  # m cannot exceed N+1 due to array length constraints

    # Precompute factorial and inverse factorial up to max_m
    max_fact = max_m
    fact = [1] * (max_fact + 1)
    for i in range(1, max_fact + 1):
        fact[i] = fact[i-1] * i % MOD

    inv_fact = [1] * (max_fact + 1)
    inv_fact[max_fact] = pow(fact[max_fact], MOD-2, MOD)
    for i in range(max_fact - 1, -1, -1):
        inv_fact[i] = inv_fact[i + 1] * (i + 1) % MOD

    def comb(m, k):
        if k < 0 or k > m:
            return 0
        return fact[m] * inv_fact[k] % MOD * inv_fact[m - k] % MOD

    total = 0
    for m in range(1, max_m + 1):
        if (m - 1) > M:
            continue

        sum_term = 0
        for k in range(0, m + 1):
            # Calculate sign: (-1)^(m-k)
            sign = -1 if (m - k) % 2 else 1
            c = comb(m, k)
            base = 2 * M - m + 1 + k
            base_mod = base % MOD
            pow_term = pow(base_mod, N, MOD)
            term = sign * c * pow_term
            term %= MOD  # Ensure term is within MOD
            sum_term = (sum_term + term) % MOD

        contribution = m * sum_term % MOD
        total = (total + contribution) % MOD

    print(total % MOD)

solve()