#include <bits/stdc++.h>

using namespace std;

template <typename T>
int pow(int x, T n, int mod = std::numeric_limits<int>::max()) {
  int res = 1;
  while (n > 0) {
    if (n & 1) res = static_cast<int64_t>(res) * static_cast<int64_t>(x) % mod;
    x = static_cast<int64_t>(x) * static_cast<int64_t>(x) % mod;
    n >>= 1;
  }
  return res;
}

template <typename T>
int64_t pow(int64_t x, T n, int64_t mod = std::numeric_limits<int64_t>::max()) {
  int64_t res = 1;
  while (n > 0) {
    if (n & 1) res = static_cast<__int128>(res) * static_cast<__int128>(x) % mod;
    x = static_cast<__int128>(x) * static_cast<__int128>(x) % mod;
    n >>= 1;
  }
  return res;
}

const int MOD = 998244353;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int64_t N, L;
  cin >> N >> L;
  cout << pow(2, (N + L - 1) / L, MOD) - 1 << '\n';
  return 0;
}