#include <bits/stdc++.h>

using namespace std;
void fast_io() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
}

#include <atcoder/modint>
using mint = atcoder::modint998244353;
int main() {
    fast_io();
    int n, k;
    cin >> n >> k;
    vector<mint> dp(n + 1), cum(n + 1);
    dp[n] = cum[n] = 1;
    for (int i = n - 1; i >= 0; i--) {
        if (i + k > n) {
            dp[i] = 1;
            cum[i] = cum[i + 1] + dp[i];
            continue;
        }
        dp[i] = cum[i + k] + 1;
        cum[i] = cum[i + 1] + dp[i];
    }
    cout << dp[0].val() << endl;
}