#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;
	if (N < L) n = 1;

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

	return 0;
}