#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
#define rep(i, n) for (int i = 0; i < (n); ++i)
 
using namespace std;
using mint = modint998244353;

int main() {
    int n, k;
    cin >> n >> k;
    
    if (k > n-k) k = n-k;
    
    mint ans = 1;
    rep(i, k) ans *= n-i;
    rep(i, k) ans /= i+1;
    
    cout << ans.val() << '\n';
    
    return 0;
}