#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
#define rep(i, n) for(ll i = 0; i < n; i++)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}
const int MAX_N = 200100;
const ll MOD = 998244353;
vector<ll> fac(MAX_N), finv(MAX_N), inv(MAX_N);
void init(){
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for(int i=2;i<MAX_N;i++){
        fac[i] = fac[i-1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD/i) % MOD;
        finv[i] = finv[i-1] * inv[i] % MOD;
    }
}
ll mcomb(int n,int k){
    if (n<k) return 0;
    if (n<0 || k<0) return 0;
    return fac[n] * (finv[k] * finv[n-k] % MOD) % MOD;
}

int main(){
    init();
    int n,k;
    cin >> n >> k;
    if(k==0 || n==k){
        cout << 1 << endl;
        return 0;
    }
    if(k==1){
        if(!(n%2)) cout << 2 << endl;
        else cout << n-2 << endl;
        return 0;
    }
    if(k==n-1){
        cout << n-2 << endl;
        return 0;
    }
    ll ans = 0;
    for(int i=0;i<=n-k;i+=2){
        ll x = mcomb(n-2-i, k-2) * (i + 1) % MOD;
        ans = (ans + x) % MOD;
    }
    cout << ans << endl;
    return 0;
}