#include<iostream>
#include<cassert>
#include<atcoder/modint>
using namespace std;
using mint=atcoder::modint998244353;
mint dp[1<<17];
mint ans;
int N,K;
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cin>>N>>K;
	dp[0]=1;
	dp[1]=-1;
	for(int i=0;i<=N;i++)
	{
		dp[i+1]+=dp[i];
		ans+=dp[i];
		if(i+K<=N)dp[i+K]+=dp[i];
	}
	cout<<ans.val()<<endl;
}