#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

#include <atcoder/modint>
using mint = atcoder::modint998244353;

int main() {
  ll n, l;
  cin >> n >> l;
  cout << (mint(2).pow((n + l - 1) / l) - 1).val() << endl;
  return 0;
}