#include<iostream>
#include<string>
#include<vector>

using namespace std;


#define int long long

constexpr int MOD = 998244353;

int power(int n, int k){
  int res = 1;

  while(k) {
    if(k&1) res *= n;

    k >>= 1;

    res %= MOD;

    n *= n;
    n %= MOD;
  }

  return res;
}

signed main(){
  int N, L;
  int ans;

  cin>>N>>L;

  ans = power(2, (N + L - 1)/L);

  ans = (MOD - 1 + ans) % MOD;

  cout<<ans<<endl;


  return 0;
}