#include<bits/stdc++.h>
#include<atcoder/modint>
using namespace std;

int main(){
  using ll=long long;
  using mint=atcoder::modint998244353;
  ll mod=998244353;
  ll n,k;
  cin>>n>>k;
  k=min(k,n-k);
  mint ans=1;
  if (n>=mod&&mod>n-k) ans=0;
  else{
    mint fact=1;
    for (int i=1;i<=k;i++) fact*=i;
    for (int i=n;i>n-k;i--) ans*=i;
    ans/=fact;
  }
  cout<<ans.val()<<endl;
}