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

typedef long long ll;
typedef pair<ll,ll> pll;
typedef modint998244353 mint;
#define rep(i,n) for(ll i=0;i<n;i++)
#define chmin(a,b) a=min(a,b)
#define chmax(a,b) a=max(a,b)
#define all(a) a.begin(),a.end()
const int INF=1001001001;

mint op(mint a,mint b){
  return a+b;
}
mint e(){return 0;}
mint mapping(mint f,mint x){
  return f+x;
}
mint id(){
  return 0;
}
mint composition(mint f,mint x){return f+x;}
int main(){
  ll n,k;
  cin>>n>>k;
  lazy_segtree<mint,op,e,mint,mapping,composition,id> seg(n+3);
  seg.set(0,1);
  rep(i,n){
    seg.apply(min(i+k,n+1),n+1,seg.get(i));
    //debug
    //rep(j,n+1)cout<<seg.get(j).val()<<" ";
    //cout<<endl;
  }
  mint ans=0;
  rep(i,n+1)ans+=seg.get(i);
  cout<<ans.val()<<endl;
}