#include<bits/stdc++.h>
#include<atcoder/modint>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
int main() {
  int N, K;
  cin >> N >> K;
  vector<mint> dp(N + 2, 0);
  vector<mint> sdp(N + 2, 0);
  //sdp[i] := dp[0] + dp[1] + ... + dp[i - 1];
  dp[0] = 1;
  for (int i = 1; i <= N + 1; i++) {
    sdp[i] += sdp[i - 1] + dp[i - 1];
    if (i - K + 1 > 0) {
      dp[i] += sdp[i - K + 1];
    }
  }
  cout << sdp[N + 1].val() << endl;
}