#include <iostream>
#include <utility>
#include <vector>
#include <string>
#include <cstdio>


using namespace std;

int main(){

    long long int n,l;
    long long int s=998244353; 
    cin>>n>>l;
    long long int ans=1;

    n=(n+l-1)/l;
    for (int i=0;i<n;i++)
        ans=(ans*2)%s;

    cout<<(ans-1)<<endl;
    
}