#include #include #include #include #include #include #include #include #define rep(i, a, b) for (int i = int(a); i < int(b); i++) using namespace std; using ll = long long int; // NOLINT using P = pair; // clang-format off #ifdef _DEBUG_ #define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; debug_print(__VA_ARGS__); } while(false) template void debug_print(const T &t, const Ts &...ts) { cerr << t; ((cerr << ", " << ts), ...); cerr << endl; } #else #define dump(...) do{ } while(false) #endif template vector make_v(size_t a, T b) { return vector(a, b); } template auto make_v(size_t a, Ts... ts) { return vector(a, make_v(ts...)); } template bool chmin(T &a, const T& b) { if (a > b) {a = b; return true; } return false; } template bool chmax(T &a, const T& b) { if (a < b) {a = b; return true; } return false; } template void print(const T& t, const Ts&... ts) { cout << t; ((cout << ' ' << ts), ...); cout << '\n'; } constexpr static struct PositiveInfinity { template constexpr operator T() const { return numeric_limits::max() / 2; } constexpr auto operator-() const; } inf; // NOLINT constexpr static struct NegativeInfinity { template constexpr operator T() const { return numeric_limits::lowest() / 2; } constexpr auto operator-() const; } NegativeInfinityVal; constexpr auto PositiveInfinity::operator-() const { return NegativeInfinityVal; } constexpr auto NegativeInfinity::operator-() const { return inf; } // clang-format on template class ModInt { ll n; auto constexpr inverse() const { return this->pow(*this, this->mod - 2); } public: constexpr static ll mod = MOD; using mint = ModInt; constexpr ModInt() : n(0) {} constexpr ModInt(const ll &nn) : n(((nn % MOD) + MOD) % MOD) {} constexpr mint operator+=(const mint &m) { n += m.n; if (n >= mint::mod) n -= mint::mod; return *this; } constexpr mint operator-=(const mint &m) { n -= m.n; if (n < 0) n += mint::mod; return *this; } constexpr mint operator*=(const mint &m) { n *= m.n; if (n >= mint::mod) n %= mint::mod; return *this; } constexpr mint operator/=(const mint &m) { return (*this) *= m.inverse(); } friend constexpr mint operator+(mint t, const mint &m) { return t += m; } friend constexpr mint operator-(mint t, const mint &m) { return t -= m; } friend constexpr mint operator*(mint t, const mint &m) { return t *= m; } friend constexpr mint operator/(mint t, const mint &m) { return t /= m; } constexpr mint operator=(const ll &l) { n = l % mint::mod; if (n < 0) n += mint::mod; return *this; } friend ostream &operator<<(ostream &out, const mint &m) { out << m.n; return out; } friend istream &operator>>(istream &in, mint &m) { ll l; in >> l; m = l; return in; } static constexpr auto pow(const mint &x, ll p) { mint ans = 1; for (auto m = x; p > 0; p /= 2, m *= m) { if (p % 2) ans *= m; } return ans; } constexpr ll get_raw() const { return n; } }; using mint = ModInt<998244353>::mint; constexpr mint operator"" _m(unsigned long long m) { return mint(m); } template class LagrangeInterpolation { std::vector x, y; public: LagrangeInterpolation(const std::vector &xp, const std::vector &yp) : x(xp), y(yp) {} T interpolate(const T &t) const { const int N = static_cast(x.size()); std::vector al(N, 1), ar(N, 1); for (int i = 0; i < N - 1; i++) { al[i + 1] = al[i] * (t - x[i]); ar[N - i - 2] = ar[N - i - 1] * (t - x[N - i - 1]); } T b = std::accumulate(next(x.begin()), x.end(), T{1}, [&](T acc, const T &xi) { return acc * (x[0] - xi); }); T ans = 0; for (uint i = 0; i < x.size(); i++) { ans += y[i] * al[i] * ar[i] / b; if (i + 1 < x.size()) { b *= x[i + 1] - x.front(); b /= x[i] - x.back(); } } return ans; } }; mint factrial[] = { 1, 913933877, 295201906, 160030060, 957629942, 545208507, 213689172, 760025067, 939830261, 506268060, 39806322, 808258749, 440133909, 686156489, 741797144, 390377694, 12629586, 544711799, 104121967, 495867250, 421290700, 117153405, 57084755, 202713771, 675932866, 79781699, 956276337, 652678397, 35212756, 655645460, 468129309, 761699708, 533047427, 287671032, 206068022, 50865043, 144980423, 111276893, 259415897, 444094191, 593907889, 573994984, 892454686, 566073550, 128761001, 888483202, 251718753, 548033568, 428105027, 742756734, 546182474, 62402409, 102052166, 826426395, 159186619, 926316039, 176055335, 51568171, 414163604, 604947226, 681666415, 511621808, 924112080, 265769800, 955559118, 763148293, 472709375, 19536133, 860830935, 290471030, 851685235, 242726978, 169855231, 612759169, 599797734, 961628039, 953297493, 62806842, 37844313, 909741023, 689361523, 887890124, 380694152, 669317759, 367270918, 806951470, 843736533, 377403437, 945260111, 786127243, 80918046, 875880304, 364983542, 623250998, 598764068, 804930040, 24257676, 214821357, 791011898, 954947696, 183092975, }; int main() { cin.tie(nullptr); ios::sync_with_stdio(false); ll n, k; cin >> n >> k; auto powsum = [&](ll kk) -> mint { vector x(kk + 2), y(kk + 2, 1); iota(x.begin(), x.end(), 1); rep(i, 0, kk + 1) { y[i + 1] = mint::pow(x[i + 1], kk) + y[i]; } LagrangeInterpolation li(x, y); return li.interpolate(n); }; constexpr int B = 10'000'000; mint ans = n * powsum(k) - powsum(k + 1); n--; ans *= 2; ans *= factrial[n / B]; rep(i, 0, n % B) { ans *= n / B * B + i + 1; } print(ans); return 0; }