def solve_problem(n, k):
    MOD = 998244353
    if k > n:
        return 0

    result = 1
    k = min(k, n - k)

    # Compute numerator product and factorial of k in one loop
    numerator = 1
    factorial_k = 1
    for i in range(1, k + 1):
        numerator = (numerator * (n - i + 1)) % MOD
        factorial_k = (factorial_k * i) % MOD

    result = numerator * pow(factorial_k, MOD - 2, MOD) % MOD

    return result
print(solve_problem(*map(int, input().split())))