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

typedef long long ll;

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;
}
int main() {
    ll N, L;
    cin >> N >> L;
    ll x = (N + L - 1) / L;
    ll MOD = 998244353;
    ll ans = (mod_pow(2, x, MOD) - 1 + MOD) % MOD;
    cout << ans << "\n";
}