#include <bits/stdc++.h>
#define NIL (-1)
#define ll long long
using namespace std;
const double PI = acos(-1.0);

int main() {
	ll N, L;
	cin >> N >> L;

	ll n = N / L;
	n += N % L;

	const ll mod = 998244353;
	ll ans = 1;
	while (n) {
		ans *= 2;
		ans %= mod;
		n--;
	}
	cout << ans - 1 << endl;

	return 0;
}