#include <iostream>
#include <vector>
#include<iomanip>
#include<functional>
#include<algorithm>
#include<deque>
#include<math.h>
#include<set>
#include<string>
#include<queue>
#include<complex>
#include<numeric>
#include<stack>
#include<map>
using namespace std;
#define rep(i,n) for(ll i = 0;i<n;i++)
#define req(i,n) for(ll i = 1;i<=n;i++)
#define rrep(i,n) for(int i = n-1;i>=0;i--)
#define ALL(a) a.begin(),a.end()
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
typedef unsigned long long ll;
typedef long double ld;
ll mod_pow(ll x, ll n, ll mod) {
    ll res = 1;
    while (n > 0) {
        if (n & 1) res = res * x % mod;
        x = x * x % mod; n >>= 1;
    }return res;
}
ll MOD = 998244353;
int main() {
    ll n, l; cin >> n >> l;
    ll t = (n - 1+l) / l;
    cout << (mod_pow(2, t, MOD) + MOD - 1) % MOD<<endl;
}