#if __INCLUDE_LEVEL__ == 0 #include __BASE_FILE__ using Mint = atcoder::modint998244353; Mint Solve(int n, int k) { auto check = [&](int i, int j) -> bool { return 0 <= min(i, j) && max(i, j) <= n && i <= j && j - i <= k; }; vector f(n + 1, vector(n + 1)); f[0][0] = 1; for (int i : Rep1(0, n)) { for (int j : Rep1(0, n)) { if (check(i, j + 1)) { f[i][j + 1] += f[i][j]; } if (check(i + 1, j)) { f[i + 1][j] += f[i][j]; } } } return f[n][n]; } void Solve() { int n, k; IN(n, k); OUT(Solve(n, k) - Solve(n, k - 1)); } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); Solve(); } #elif __INCLUDE_LEVEL__ == 1 #include #include template concept MyRange = std::ranges::range && !std::convertible_to; template concept MyTuple = std::__is_tuple_like::value && !MyRange; namespace std { istream& operator>>(istream& is, MyRange auto&& r) { for (auto&& e : r) is >> e; return is; } istream& operator>>(istream& is, MyTuple auto&& t) { apply([&](auto&... xs) { (is >> ... >> xs); }, t); return is; } ostream& operator<<(ostream& os, MyRange auto&& r) { auto sep = ""; for (auto&& e : r) os << exchange(sep, " ") << e; return os; } ostream& operator<<(ostream& os, MyTuple auto&& t) { auto sep = ""; apply([&](auto&... xs) { ((os << exchange(sep, " ") << xs), ...); }, t); return os; } template * = nullptr> istream& operator>>(istream& is, T& x) { int v; is >> v; x = T::raw(v); return is; } template * = nullptr> ostream& operator<<(ostream& os, const T& x) { return os << x.val(); } } // namespace std using namespace std; #define Rep(...) [](int l, int r) { return views::iota(min(l, r), r); }(__VA_ARGS__) #define Rep1(...) [](int l, int r) { return Rep(l, r + 1); }(__VA_ARGS__) #define IN(...) (cin >> forward_as_tuple(__VA_ARGS__)) #define OUT(...) (cout << forward_as_tuple(__VA_ARGS__) << '\n') #endif // __INCLUDE_LEVEL__ == 1