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

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

    for i in range(1, k + 1):
        result = (result * (n - i + 1)) % MOD
        result = (result * pow(i, MOD - 2, MOD)) % MOD

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