#define MD 998244353
ll@n,@k;
Mint a[n+1],b[n+1];
a[0]=1;
b[0]=1;
rep(i,1,n+1){
	if(i>=k){
		a[i]=b[i-k];
	}
	b[i]=b[i-1]+a[i];
}
wt(b[n]);