#include <bits/stdc++.h>
#include <atcoder/all>

using namespace std;
using ll = long long;
using mint = atcoder::modint998244353;

constexpr ll MOD = 998244353LL;

int main() {
    int N, K; cin >> N >> K;
    K = min(K, N - K);

    ll ans = 1LL;
    ll div = 1LL;
    for (int i = 0; i < K; i++) {
        ans = ans * (N - i) % MOD;
        div = div * (K - i) % MOD;
    }

    cout << (mint(ans) / mint(div)).val() << endl;
}