#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const ll M = 998244353;
ll fpow(ll x, ll n){
    ll ret = 1;
    while(n){
        if(n % 2) ret = ret * x % M;
        x = x * x % M;
        n >>= 1;
    }
    return ret;
}
ll C(ll n, ll m){
    if(m == 0) return 1;
    if(n < m) return 0;
    if(n - m < m) m = n - m;
    if(n >= M) return C(n / M, m / M) * C(n % M, m % M) % M;
    ll fz = 1, fm = 1;
    for(int i = 1; i <= m; i++){
        fm = fm * i % M;
        fz = fz * (n - i + 1) % M;
    }
    return fz * fpow(fm, M - 2) % M;
}

int main(){
    ll n, k;
    cin >> n >> k;
    cout << C(n, k) << endl;
    return 0;
}