//埋め込み想定だったらキレる
#pragma GCC optimize ("O3","unroll-loops")
#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using mint = atcoder::modint998244353;

int main(){
    int n, k;
    cin >> n >> k;
    k = min(k, n - k);
    if(n - k + 1 <= 998244353 && 998244353 <= n){
        cout << "0\n";
        return 0;
    }
    mint mul = 1, div = 1;
    for(int i = 0; i < k; i++){
        mul *= mint::raw(n - i);
        div *= mint::raw(i + 1);
    }
    cout << (mul / div).val() << '\n';
}