MOD = 998244353

def main():
    a, b = map(int, input().split())
    n = a + b - 2
    k = a - 1

    # Precompute factorial and inverse factorial up to required maximum
    max_n = n  # Since n is the maximum needed value
    fact = [1] * (max_n + 1)
    for i in range(1, max_n + 1):
        fact[i] = fact[i-1] * i % MOD

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

    # Compute combination(n, k)
    if k < 0 or k > n:
        print(0)
    else:
        ans = fact[n] * inv_fact[k] % MOD
        ans = ans * inv_fact[n - k] % MOD
        print(ans)

if __name__ == '__main__':
    main()