#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i < (n); i++)
using namespace std;
using ll = long long;

ll mod = 998244353;

int main(){
    ios::sync_with_stdio(false);
    ll N,L; cin>>N>>L;
    N = N/L + N%L;
    cerr << N << endl;

    ll ans=1;
    while(N--){
        ans *= 2;
        ans %= mod;
    }
    cout << ans - 1 << endl;

}