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

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

    inv = [0] * (k + 1)
    if k >= 1:
        inv[1] = 1
        for i in range(2, k + 1):
            inv[i] = MOD - (MOD // i) * inv[MOD % i] % MOD

    for i in range(1, k + 1):
        result = (result * (n - i + 1)) % MOD
        result = (result * inv[i]) % MOD

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