#include <bits/stdc++.h>
using namespace std;
long long mod=998244353;
#define int long long
signed main(){
    long long N,L; cin>>N>>L;
    long long count=(N+L-1)/L;
    long long ans=pow(2,count);
    ans--;
    if(ans<0)ans+=((abs(ans)+mod-1)/mod)*mod;
    ans%=mod;
    cout<<ans<<endl;
}