#include #include #define rep(i,n) for(int i=0;i vi; typedef vector vl; typedef vector> vvi; typedef vector> vvl; typedef long double ld; typedef pair P; ostream& operator<<(ostream& os, const modint& a) {os << a.val(); return os;} template ostream& operator<<(ostream& os, const static_modint& a) {os << a.val(); return os;} template ostream& operator<<(ostream& os, const dynamic_modint& a) {os << a.val(); return os;} template istream& operator>>(istream& is, vector& v){int n = v.size(); assert(n > 0); rep(i, n) is >> v[i]; return is;} template ostream& operator<<(ostream& os, const pair& p){os << p.first << ' ' << p.second; return os;} template ostream& operator<<(ostream& os, const vector& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : " "); return os;} template ostream& operator<<(ostream& os, const vector>& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : ""); return os;} template ostream& operator<<(ostream& os, const set& se){for(T x : se) os << x << " "; os << "\n"; return os;} template ostream& operator<<(ostream& os, const unordered_set& se){for(T x : se) os << x << " "; os << "\n"; return os;} template ostream& operator<<(ostream& os, const atcoder::segtree& seg){int n = seg.max_right(0, [](S){return true;}); rep(i, n) os << seg.get(i) << (i == n - 1 ? "\n" : " "); return os;} template ostream& operator<<(ostream& os, const atcoder::lazy_segtree& seg){int n = seg.max_right(0, [](S){return true;}); rep(i, n) os << seg.get(i) << (i == n - 1 ? "\n" : " "); return os;} template void chmin(T& a, T b){a = min(a, b);} template void chmax(T& a, T b){a = max(a, b);} using mint = modint998244353; // combination mod prime // https://youtu.be/8uowVvQ_-Mo?t=6002 // https://youtu.be/Tgd_zLfRZOQ?t=9928 struct modinv { int n; vector d; modinv(): n(2), d({0,1}) {} mint operator()(int i) { while (n <= i) d.push_back(-d[mint::mod()%n]*(mint::mod()/n)), ++n; return d[i]; } mint operator[](int i) const { return d[i];} } invs; struct modfact { int n; vector d; modfact(): n(2), d({1,1}) {} mint operator()(int i) { while (n <= i) d.push_back(d.back()*n), ++n; return d[i]; } mint operator[](int i) const { return d[i];} } facts; struct modfactinv { int n; vector d; modfactinv(): n(2), d({1,1}) {} mint operator()(int i) { while (n <= i) d.push_back(d.back()*invs(n)), ++n; return d[i]; } mint operator[](int i) const { return d[i];} } ifacts; mint comb(int n, int k) { if (n < k || k < 0) return 0; return facts(n)*ifacts(k)*ifacts(n-k); } template< typename T > struct FormalPowerSeries : vector< T > { using vector< T >::vector; using P = FormalPowerSeries; template FormalPowerSeries(Args...args): vector(args...) {} FormalPowerSeries(initializer_list a): vector(a.begin(),a.end()) {} using MULT = function< P(P, P) >; static MULT &get_mult() { static MULT mult = [&](P a, P b){ P res(convolution(a, b)); return res; }; return mult; } static void set_fft(MULT f) { get_mult() = f; } void shrink() { while(this->size() && this->back() == T(0)) this->pop_back(); } P operator+(const P &r) const { return P(*this) += r; } P operator+(const T &v) const { return P(*this) += v; } P operator-(const P &r) const { return P(*this) -= r; } P operator-(const T &v) const { return P(*this) -= v; } P operator*(const P &r) const { return P(*this) *= r; } P operator*(const T &v) const { return P(*this) *= v; } P operator/(const P &r) const { return P(*this) /= r; } P operator%(const P &r) const { return P(*this) %= r; } P &operator+=(const P &r) { if(r.size() > this->size()) this->resize(r.size()); for(int i = 0; i < int(r.size()); i++) (*this)[i] += r[i]; return *this; } P &operator+=(const T &r) { if(this->empty()) this->resize(1); (*this)[0] += r; return *this; } P &operator-=(const P &r) { if(r.size() > this->size()) this->resize(r.size()); for(int i = 0; i < int(r.size()); i++) (*this)[i] -= r[i]; // shrink(); return *this; } P &operator-=(const T &r) { if(this->empty()) this->resize(1); (*this)[0] -= r; // shrink(); return *this; } P &operator*=(const T &v) { const int n = (int) this->size(); for(int k = 0; k < n; k++) (*this)[k] *= v; return *this; } P &operator*=(const P &r) { if(this->empty() || r.empty()) { this->clear(); return *this; } assert(get_mult() != nullptr); return *this = get_mult()(*this, r); } P &operator%=(const P &r) { return *this -= *this / r * r; } P operator-() const { P ret(this->size()); for(int i = 0; i < int(this->size()); i++) ret[i] = -(*this)[i]; return ret; } P &operator/=(const P &r) { if(this->size() < r.size()) { this->clear(); return *this; } int n = this->size() - r.size() + 1; return *this = (rev().pre(n) * r.rev().inv(n)).pre(n).rev(n); } P pre(int sz) const { return P(begin(*this), begin(*this) + min((int) this->size(), sz)); } P operator>>(int sz) const { if((int)this->size() <= sz) return {}; P ret(*this); ret.erase(ret.begin(), ret.begin() + sz); return ret; } P operator<<(int sz) const { P ret(*this); ret.insert(ret.begin(), sz, T(0)); return ret; } P rev(int deg = -1) const { P ret(*this); if(deg != -1) ret.resize(deg, T(0)); reverse(begin(ret), end(ret)); return ret; } P diff() const { const int n = (int) this->size(); P ret(max(0, n - 1)); for(int i = 1; i < n; i++) ret[i - 1] = (*this)[i] * T(i); return ret; } P integral() const { const int n = (int) this->size(); P ret(n + 1); ret[0] = T(0); for(int i = 0; i < n; i++) ret[i + 1] = (*this)[i] / T(i + 1); return ret; } // F(0) must not be 0 P inv(int deg = -1) const { assert(((*this)[0]) != T(0)); const int n = (int) this->size(); if(deg == -1) deg = n; P ret({T(1) / (*this)[0]}); for(int i = 1; i < deg; i <<= 1) { ret = (ret + ret - ret * ret * pre(i << 1)).pre(i << 1); } return ret.pre(deg); } // F(0) must be 1 P log(int deg = -1) const { assert((*this)[0] == T(1)); const int n = (int) this->size(); if(deg == -1) deg = n; return (this->diff() * this->inv(deg)).pre(deg - 1).integral(); } // F(0) must be 0 P exp(int deg = -1) const { assert((*this)[0] == T(0)); const int n = (int) this->size(); if(deg == -1) deg = n; P ret({T(1)}); for(int i = 1; i < deg; i <<= 1) { ret = (ret * (pre(i << 1) + T(1) - ret.log(i << 1))).pre(i << 1); } return ret.pre(deg); } P pow(int k, int deg = -1) const { const int n = (int) this->size(); if(deg == -1) deg = n; for(int i = 0; i < n; i++) { if((*this)[i] != T(0)) { T rev = T(1) / (*this)[i]; P C(*this * rev); P D(n - i); for(int j = i; j < n; j++) D[j - i] = C[j]; D = (D.log(deg) * T(k)).exp() * (*this)[i].pow(k); P E(deg); if(i * k > deg) return E; auto S = i * k; for(int j = 0; j + S < deg && j < D.size(); j++) E[j + S] = D[j]; return E; } } return *this; } }; template void infer(vector v){for(auto& a : v) infer(a); cout << "\n";} using FPS = FormalPowerSeries; int main(){ int n, K; cin >> n >> K; mint ans = 0; vector frequency_a(K + 1); rep(i, n){ int a; cin >> a; frequency_a[min(a, K)]++; } map frequency_p; for(int i = 1; i <= K; i++){ int p = gcd(K, i); frequency_p[p]++; } vector f(K + 1, FPS(K + 1)); f[0][0] = 1; for(int k = 1; k <= K; k++){ f[k] = f[k - 1]; f[k][k] = ifacts(k); } vector f_log(K + 1, FPS(K + 1)); rep(k, K + 1) f_log[k] = f[k].log(); for(auto [p, c] : frequency_p){ int q = K / p; vector frequency_b(p + 1); for(int a = 1; a <= K; a++){ int b = a / q; frequency_b[b] += frequency_a[a]; } FPS g_log(p + 1); for(int b = 1; b <= p; b++){ g_log += f_log[b] * mint(frequency_b[b]); } FPS g = g_log.exp(); ans += g[p] * facts(p) * c; } cout << ans / K << "\n"; return 0; }