#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 fac(ll n){
    ll ret = 1;
    if(n < M / 2){
        for(int i = 2; i <= n; i++) ret = ret * i % M;
    }else{
        for(int i = n + 1; i < M; i++) ret = ret * i % M;
        ret = (M - 1) * fpow(ret, M - 2) % M;
    }
    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;
    return fac(n) * fpow(fac(m), M - 2) % M * fpow(fac(n - m), M - 2) % M;
}

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