#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
const ll mod = 998244353;
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    fixed(cout).precision(12);
    ll N, K; cin >> N >> K;
    vector<ll> dp(N + 1, 0);
    dp[0] = 1;
    for(int i = 1; i <= N; i++) if(i - K >= 0) dp[i] = (dp[i - K] + dp[i - 1]) % mod;
    ll ans = 0;
    for(auto a: dp) (ans += a) %= mod;
    cout << ans << endl;
}