#include #pragma GCC target("popcnt") #include #include #ifndef __GNUC__ int __builtin_ctz(const unsigned int c) noexcept { static constexpr std::array table = { 0, 1, 2, 6, 3, 11, 7, 16, 4, 14, 12, 21, 8, 23, 17, 26, 31, 5, 10, 15, 13, 20, 22, 25, 30, 9, 19, 24, 29, 18, 28, 27 }; return table[(c & ~c + 1) * 0x4653ADF >> 27 & 0x1F]; } int __builtin_ctzll(const unsigned long long c) noexcept { static constexpr std::array table = { 0, 1, 2, 7, 3, 13, 8, 27, 4, 33, 14, 36, 9, 49, 28, 19, 5, 25, 34, 17, 15, 53, 37, 55, 10, 46, 50, 39, 29, 42, 20, 57, 63, 6, 12, 26, 32, 35, 48, 18, 24, 16, 52, 54, 45, 38, 41, 56, 62, 11, 31, 47, 23, 51, 44, 40, 61, 30, 22, 43, 60, 21, 59, 58 }; return table[(c & ~c + 1) * 0x218A7A392DD9ABFULL >> 58 & 0x3F]; } int __builtin_clz(unsigned int c) noexcept { static constexpr std::array table = { 0, 1, 2, 6, 3, 11, 7, 16, 4, 14, 12, 21, 8, 23, 17, 26, 31, 5, 10, 15, 13, 20, 22, 25, 30, 9, 19, 24, 29, 18, 28, 27 }; c |= c >> 1; c |= c >> 2; c |= c >> 4; c |= c >> 8; c |= c >> 16; return table[((c >> 1) + 1) * 0x4653ADF >> 27 & 0x1F]; } int __builtin_clzll(unsigned long long c) noexcept { static constexpr std::array table = { 0, 1, 2, 7, 3, 13, 8, 27, 4, 33, 14, 36, 9, 49, 28, 19, 5, 25, 34, 17, 15, 53, 37, 55, 10, 46, 50, 39, 29, 42, 20, 57, 63, 6, 12, 26, 32, 35, 48, 18, 24, 16, 52, 54, 45, 38, 41, 56, 62, 11, 31, 47, 23, 51, 44, 40, 61, 30, 22, 43, 60, 21, 59, 58 }; c |= c >> 1; c |= c >> 2; c |= c >> 4; c |= c >> 8; c |= c >> 16; c |= c >> 32; return table[((c >> 1) + 1) * 0x218A7A392DD9ABFULL >> 58 & 0x3F]; } constexpr int __builtin_popcount(unsigned int c) noexcept { c -= c >> 1 & 0x55555555; c = (c & 0x33333333) + (c >> 2 & 0x33333333); c = (c + (c >> 4)) & 0x0F0F0F0F; return c * 0x01010101 >> 24 & 0x3F; } constexpr int __builtin_popcountll(unsigned long long c) noexcept { c -= c >> 1 & 0x5555555555555555; c = (c & 0x3333333333333333) + (c >> 2 & 0x3333333333333333); c = (c + (c >> 4)) & 0x0F0F0F0F0F0F0F0F; return c * 0x0101010101010101 >> 56 & 0x7f; } constexpr bool __builtin_parity(unsigned int c) noexcept { c ^= c >> 1; c ^= c >> 2; return ((c & 0x11111111) * 0x11111111 >> 28 & 0x1) != 0; } constexpr bool __builtin_parityll(unsigned long long c) noexcept { c ^= c >> 1; c ^= c >> 2; return ((c & 0x1111111111111111) * 0x1111111111111111 >> 60 & 0x1) != 0; } #endif using namespace std; // https://ei1333.github.io/library/test/verify/yosupo-inv-of-formal-power-series.test.cpp // #line 1 "test/verify/yosupo-inv-of-formal-power-series.test.cpp" #define PROBLEM "https://judge.yosupo.jp/problem/inv_of_formal_power_series" // #line 1 "template/template.cpp" #include using namespace std; using int64 = long long; const int mod = 1e9 + 7; const int64 infll = (1LL << 62) - 1; const int inf = (1 << 30) - 1; struct IoSetup { IoSetup() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(10); cerr << fixed << setprecision(10); } } iosetup; template ostream& operator<<(ostream& os, const pair& p) { os << p.first << " " << p.second; return os; } template istream& operator>>(istream& is, pair& p) { is >> p.first >> p.second; return is; } template ostream& operator<<(ostream& os, const vector& v) { for (int i = 0; i < (int)v.size(); i++) { os << v[i] << (i + 1 != v.size() ? " " : ""); } return os; } template istream& operator>>(istream& is, vector& v) { for (T& in : v) is >> in; return is; } template inline bool chmax(T1& a, T2 b) { return a < b && (a = b, true); } template inline bool chmin(T1& a, T2 b) { return a > b && (a = b, true); } template vector make_v(size_t a) { return vector(a); } template auto make_v(size_t a, Ts... ts) { return vector(ts...))>(a, make_v(ts...)); } template typename enable_if::value == 0>::type fill_v(T& t, const V& v) { t = v; } template typename enable_if::value != 0>::type fill_v(T& t, const V& v) { for (auto& e : t) fill_v(e, v); } template struct FixPoint : F { explicit FixPoint(F&& f) : F(forward(f)) {} template decltype(auto) operator()(Args &&... args) const { return F::operator()(*this, forward(args)...); } }; template inline decltype(auto) MFP(F&& f) { return FixPoint{forward(f)}; } // #line 4 "test/verify/yosupo-inv-of-formal-power-series.test.cpp" // #line 1 "math/combinatorics/mod-int.cpp" template struct ModInt { int x; ModInt() : x(0) {} ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {} ModInt& operator+=(const ModInt& p) { if ((x += p.x) >= mod) x -= mod; return *this; } ModInt& operator-=(const ModInt& p) { if ((x += mod - p.x) >= mod) x -= mod; return *this; } ModInt& operator*=(const ModInt& p) { x = (int)(1LL * x * p.x % mod); return *this; } ModInt& operator/=(const ModInt& p) { *this *= p.inverse(); return *this; } ModInt operator-() const { return ModInt(-x); } ModInt operator+(const ModInt& p) const { return ModInt(*this) += p; } ModInt operator-(const ModInt& p) const { return ModInt(*this) -= p; } ModInt operator*(const ModInt& p) const { return ModInt(*this) *= p; } ModInt operator/(const ModInt& p) const { return ModInt(*this) /= p; } bool operator==(const ModInt& p) const { return x == p.x; } bool operator!=(const ModInt& p) const { return x != p.x; } ModInt inverse() const { int a = x, b = mod, u = 1, v = 0, t; while (b > 0) { t = a / b; swap(a -= t * b, b); swap(u -= t * v, v); } return ModInt(u); } ModInt pow(int64_t n) const { ModInt ret(1), mul(x); while (n > 0) { if (n & 1) ret *= mul; mul *= mul; n >>= 1; } return ret; } friend ostream& operator<<(ostream& os, const ModInt& p) { return os << p.x; } friend istream& operator>>(istream& is, ModInt& a) { int64_t t; is >> t; a = ModInt(t); return (is); } static int get_mod() { return mod; } }; using modint = ModInt; // #line 1 "math/fft/number-theoretic-transform-friendly-mod-int.cpp" /** * @brief Number Theoretic Transform Friendly ModInt */ template struct NumberTheoreticTransformFriendlyModInt { static vector roots, iroots, rate3, irate3; static int max_base; NumberTheoreticTransformFriendlyModInt() = default; static void init() { if (roots.empty()) { const unsigned mod = Mint::get_mod(); assert(mod >= 3 && mod % 2 == 1); auto tmp = mod - 1; max_base = 0; while (tmp % 2 == 0) tmp >>= 1, max_base++; Mint root = 2; while (root.pow((mod - 1) >> 1) == 1) { root += 1; } assert(root.pow(mod - 1) == 1); roots.resize(max_base + 1); iroots.resize(max_base + 1); rate3.resize(max_base + 1); irate3.resize(max_base + 1); roots[max_base] = root.pow((mod - 1) >> max_base); iroots[max_base] = Mint(1) / roots[max_base]; for (int i = max_base - 1; i >= 0; i--) { roots[i] = roots[i + 1] * roots[i + 1]; iroots[i] = iroots[i + 1] * iroots[i + 1]; } { Mint prod = 1, iprod = 1; for (int i = 0; i <= max_base - 3; i++) { rate3[i] = roots[i + 3] * prod; irate3[i] = iroots[i + 3] * iprod; prod *= iroots[i + 3]; iprod *= roots[i + 3]; } } } } static void ntt(vector& a) { init(); const int n = (int)a.size(); assert((n & (n - 1)) == 0); int h = __builtin_ctz(n); assert(h <= max_base); int len = 0; Mint imag = roots[2]; if (h & 1) { int p = 1 << (h - 1); Mint rot = 1; for (int i = 0; i < p; i++) { auto r = a[i + p]; a[i + p] = a[i] - r; a[i] += r; } len++; } for (; len + 1 < h; len += 2) { int p = 1 << (h - len - 2); { // s = 0 for (int i = 0; i < p; i++) { auto a0 = a[i]; auto a1 = a[i + p]; auto a2 = a[i + 2 * p]; auto a3 = a[i + 3 * p]; auto a1na3imag = (a1 - a3) * imag; auto a0a2 = a0 + a2; auto a1a3 = a1 + a3; auto a0na2 = a0 - a2; a[i] = a0a2 + a1a3; a[i + 1 * p] = a0a2 - a1a3; a[i + 2 * p] = a0na2 + a1na3imag; a[i + 3 * p] = a0na2 - a1na3imag; } } Mint rot = rate3[0]; for (int s = 1; s < (1 << len); s++) { int offset = s << (h - len); Mint rot2 = rot * rot; Mint rot3 = rot2 * rot; for (int i = 0; i < p; i++) { auto a0 = a[i + offset]; auto a1 = a[i + offset + p] * rot; auto a2 = a[i + offset + 2 * p] * rot2; auto a3 = a[i + offset + 3 * p] * rot3; auto a1na3imag = (a1 - a3) * imag; auto a0a2 = a0 + a2; auto a1a3 = a1 + a3; auto a0na2 = a0 - a2; a[i + offset] = a0a2 + a1a3; a[i + offset + 1 * p] = a0a2 - a1a3; a[i + offset + 2 * p] = a0na2 + a1na3imag; a[i + offset + 3 * p] = a0na2 - a1na3imag; } rot *= rate3[__builtin_ctz(~s)]; } } } static void intt(vector& a, bool f = true) { init(); const int n = (int)a.size(); assert((n & (n - 1)) == 0); int h = __builtin_ctz(n); assert(h <= max_base); int len = h; Mint iimag = iroots[2]; for (; len > 1; len -= 2) { int p = 1 << (h - len); { // s = 0 for (int i = 0; i < p; i++) { auto a0 = a[i]; auto a1 = a[i + 1 * p]; auto a2 = a[i + 2 * p]; auto a3 = a[i + 3 * p]; auto a2na3iimag = (a2 - a3) * iimag; auto a0na1 = a0 - a1; auto a0a1 = a0 + a1; auto a2a3 = a2 + a3; a[i] = a0a1 + a2a3; a[i + 1 * p] = (a0na1 + a2na3iimag); a[i + 2 * p] = (a0a1 - a2a3); a[i + 3 * p] = (a0na1 - a2na3iimag); } } Mint irot = irate3[0]; for (int s = 1; s < (1 << (len - 2)); s++) { int offset = s << (h - len + 2); Mint irot2 = irot * irot; Mint irot3 = irot2 * irot; for (int i = 0; i < p; i++) { auto a0 = a[i + offset]; auto a1 = a[i + offset + 1 * p]; auto a2 = a[i + offset + 2 * p]; auto a3 = a[i + offset + 3 * p]; auto a2na3iimag = (a2 - a3) * iimag; auto a0na1 = a0 - a1; auto a0a1 = a0 + a1; auto a2a3 = a2 + a3; a[i + offset] = a0a1 + a2a3; a[i + offset + 1 * p] = (a0na1 + a2na3iimag) * irot; a[i + offset + 2 * p] = (a0a1 - a2a3) * irot2; a[i + offset + 3 * p] = (a0na1 - a2na3iimag) * irot3; } irot *= irate3[__builtin_ctz(~s)]; } } if (len >= 1) { int p = 1 << (h - 1); for (int i = 0; i < p; i++) { auto ajp = a[i] - a[i + p]; a[i] += a[i + p]; a[i + p] = ajp; } } if (f) { Mint inv_sz = Mint(1) / n; for (int i = 0; i < n; i++) a[i] *= inv_sz; } } static vector multiply(vector a, vector b) { int need = a.size() + b.size() - 1; int nbase = 1; while ((1 << nbase) < need) nbase++; int sz = 1 << nbase; a.resize(sz, 0); b.resize(sz, 0); ntt(a); ntt(b); Mint inv_sz = Mint(1) / sz; for (int i = 0; i < sz; i++) a[i] *= b[i] * inv_sz; intt(a, false); a.resize(need); return a; } }; template vector NumberTheoreticTransformFriendlyModInt::roots = vector(); template vector NumberTheoreticTransformFriendlyModInt::iroots = vector(); template vector NumberTheoreticTransformFriendlyModInt::rate3 = vector(); template vector NumberTheoreticTransformFriendlyModInt::irate3 = vector(); template int NumberTheoreticTransformFriendlyModInt::max_base = 0; // #line 2 "math/fps/formal-power-series-friendly-ntt.cpp" /** * @brief Formal Power Series Friendly NTT(NTTmod用形式的冪級数) * @docs docs/formal-power-series-friendly-ntt.md */ template struct FormalPowerSeriesFriendlyNTT : vector { using vector::vector; using P = FormalPowerSeriesFriendlyNTT; using NTT = NumberTheoreticTransformFriendlyModInt; P pre(int deg) const { return P(begin(*this), begin(*this) + min((int)this->size(), deg)); } P rev(int deg = -1) const { P ret(*this); if (deg != -1) ret.resize(deg, T(0)); reverse(begin(ret), end(ret)); return ret; } 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 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; } // https://judge.yosupo.jp/problem/convolution_mod P& operator*=(const P& r) { if (this->empty() || r.empty()) { this->clear(); return *this; } auto ret = NTT::multiply(*this, r); return *this = { begin(ret), end(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& operator%=(const P& r) { *this -= *this / r * r; shrink(); return *this; } // https://judge.yosupo.jp/problem/division_of_polynomials pair div_mod(const P& r) { P q = *this / r; P x = *this - q * r; x.shrink(); return make_pair(q, x); } 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 T& r) { if (this->empty()) this->resize(1); (*this)[0] += r; return *this; } P& operator-=(const T& r) { if (this->empty()) this->resize(1); (*this)[0] -= r; return *this; } P& operator*=(const T& v) { for (int i = 0; i < (int)this->size(); i++) (*this)[i] *= v; return *this; } P dot(P r) const { P ret(min(this->size(), r.size())); for (int i = 0; i < (int)ret.size(); i++) ret[i] = (*this)[i] * r[i]; return ret; } 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; } T operator()(T x) const { T r = 0, w = 1; for (auto& v : *this) { r += w * v; w *= x; } return r; } 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; } // https://judge.yosupo.jp/problem/inv_of_formal_power_series // 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 res(deg); res[0] = { T(1) / (*this)[0] }; for (int d = 1; d < deg; d <<= 1) { P f(2 * d), g(2 * d); for (int j = 0; j < min(n, 2 * d); j++) f[j] = (*this)[j]; for (int j = 0; j < d; j++) g[j] = res[j]; NTT::ntt(f); NTT::ntt(g); f = f.dot(g); NTT::intt(f); for (int j = 0; j < d; j++) f[j] = 0; NTT::ntt(f); for (int j = 0; j < 2 * d; j++) f[j] *= g[j]; NTT::intt(f); for (int j = d; j < min(2 * d, deg); j++) res[j] = -f[j]; } return res; } // https://judge.yosupo.jp/problem/log_of_formal_power_series // 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(); } // https://judge.yosupo.jp/problem/sqrt_of_formal_power_series P sqrt(int deg = -1, const function& get_sqrt = [](T) { return T(1); }) const { const int n = (int)this->size(); if (deg == -1) deg = n; if ((*this)[0] == T(0)) { for (int i = 1; i < n; i++) { if ((*this)[i] != T(0)) { if (i & 1) return {}; if (deg - i / 2 <= 0) break; auto ret = (*this >> i).sqrt(deg - i / 2, get_sqrt); if (ret.empty()) return {}; ret = ret << (i / 2); if ((int)ret.size() < deg) ret.resize(deg, T(0)); return ret; } } return P(deg, 0); } auto sqr = T(get_sqrt((*this)[0])); if (sqr * sqr != (*this)[0]) return {}; P ret{ sqr }; T inv2 = T(1) / T(2); for (int i = 1; i < deg; i <<= 1) { ret = (ret + pre(i << 1) * ret.inv(i << 1)) * inv2; } return ret.pre(deg); } P sqrt(const function& get_sqrt, int deg = -1) const { return sqrt(deg, get_sqrt); } // https://judge.yosupo.jp/problem/exp_of_formal_power_series // F(0) must be 0 P exp(int deg = -1) const { if (deg == -1) deg = this->size(); assert((*this)[0] == T(0)); P inv; inv.reserve(deg + 1); inv.push_back(T(0)); inv.push_back(T(1)); auto inplace_integral = [&](P& F) -> void { const int n = (int)F.size(); auto mod = T::get_mod(); while ((int)inv.size() <= n) { int i = inv.size(); inv.push_back((-inv[mod % i]) * (mod / i)); } F.insert(begin(F), T(0)); for (int i = 1; i <= n; i++) F[i] *= inv[i]; }; auto inplace_diff = [](P& F) -> void { if (F.empty()) return; F.erase(begin(F)); T coeff = 1, one = 1; for (int i = 0; i < (int)F.size(); i++) { F[i] *= coeff; coeff += one; } }; P b{ 1, 1 < (int)this->size() ? (*this)[1] : 0 }, c{ 1 }, z1, z2{ 1, 1 }; for (int m = 2; m < deg; m *= 2) { auto y = b; y.resize(2 * m); NTT::ntt(y); z1 = z2; P z(m); for (int i = 0; i < m; ++i) z[i] = y[i] * z1[i]; NTT::intt(z); fill(begin(z), begin(z) + m / 2, T(0)); NTT::ntt(z); for (int i = 0; i < m; ++i) z[i] *= -z1[i]; NTT::intt(z); c.insert(end(c), begin(z) + m / 2, end(z)); z2 = c; z2.resize(2 * m); NTT::ntt(z2); P x(begin(*this), begin(*this) + min(this->size(), m)); inplace_diff(x); x.push_back(T(0)); NTT::ntt(x); for (int i = 0; i < m; ++i) x[i] *= y[i]; NTT::intt(x); x -= b.diff(); x.resize(2 * m); for (int i = 0; i < m - 1; ++i) x[m + i] = x[i], x[i] = T(0); NTT::ntt(x); for (int i = 0; i < 2 * m; ++i) x[i] *= z2[i]; NTT::intt(x); x.pop_back(); inplace_integral(x); for (int i = m; i < min(this->size(), 2 * m); ++i) x[i] += (*this)[i]; fill(begin(x), begin(x) + m, T(0)); NTT::ntt(x); for (int i = 0; i < 2 * m; ++i) x[i] *= y[i]; NTT::intt(x); b.insert(end(b), begin(x) + m, end(x)); } return P{ begin(b), begin(b) + deg }; } // https://judge.yosupo.jp/problem/pow_of_formal_power_series P pow(int64_t 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 ret = (((*this * rev) >> i).log() * k).exp() * ((*this)[i].pow(k)); if (i * k > deg) return P(deg, T(0)); ret = (ret << (i * k)).pre(deg); if ((int)ret.size() < deg) ret.resize(deg, T(0)); return ret; } } return *this; } P mod_pow(int64_t k, P g) const { P modinv = g.rev().inv(); auto get_div = [&](P base) { if (base.size() < g.size()) { base.clear(); return base; } int n = base.size() - g.size() + 1; return (base.rev().pre(n) * modinv.pre(n)).pre(n).rev(n); }; P x(*this), ret{ 1 }; while (k > 0) { if (k & 1) { ret *= x; ret -= get_div(ret) * g; ret.shrink(); } x *= x; x -= get_div(x) * g; x.shrink(); k >>= 1; } return ret; } // https://judge.yosupo.jp/problem/polynomial_taylor_shift P taylor_shift(T c) const { int n = (int)this->size(); vector fact(n), rfact(n); fact[0] = rfact[0] = T(1); for (int i = 1; i < n; i++) fact[i] = fact[i - 1] * T(i); rfact[n - 1] = T(1) / fact[n - 1]; for (int i = n - 1; i > 1; i--) rfact[i - 1] = rfact[i] * T(i); P p(*this); for (int i = 0; i < n; i++) p[i] *= fact[i]; p = p.rev(); P bs(n, T(1)); for (int i = 1; i < n; i++) bs[i] = bs[i - 1] * c * rfact[i] * fact[i - 1]; p = (p * bs).pre(n); p = p.rev(); for (int i = 0; i < n; i++) p[i] *= rfact[i]; return p; } }; template using FPS = FormalPowerSeriesFriendlyNTT; // #line 7 "test/verify/yosupo-inv-of-formal-power-series.test.cpp" const int MOD = 998244353; using mint = ModInt; int main() { int N, M; cin >> N >> M; FPS G(N + 1, 0); G[0] = 1; for (int i = 0; i < M; i++) { int l; cin >> l; G[l] = 1; } cout << G.pow(N + 1)[N] / (N + 1) << "\n"; return 0; }