#include <bits/stdc++.h>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)n; i++)
#define MOD 998244353
using ll = long long int;

int main() {
  int N, K;
  cin >> N >> K;
  vector<int> dp(N+1, 0);
  dp[0] = 1;
  rep(i, N) {
    if (i+1 >= K) {
      if (K == 1 && i == 0)
	dp[i+1] = ((ll)dp[i+1] + (ll)dp[i]) % MOD;
      else
	dp[i+1] = ((ll)dp[i+1] + (ll)dp[i] + (ll)dp[(i+1)-K]) % MOD;
    }
  }
  int ans = 0;
  rep(i, N+1)
    ans = ((ll)ans + (ll)dp[i]) % MOD;
  cout << ans << endl;
  return 0;
}