#include<bits/stdc++.h>
#define int long long
using namespace std;
const int mod=998244353;
int p(int a,int b){
  if(!b)return 1;
  if(b%2)return p(a,b-1)*a%mod;
  int c=p(a,b/2);
  return c*c%mod;
}
signed main(){
  int N,L;
  cin>>N>>L;
  cout<<p(2,(N+L-1)/L)-1<<endl;
}