#include using namespace std; using ll = long long; using ull = unsigned long long; using i128 = __int128_t; using pii = pair; using pll = pair; template using vec = vector; template using vvec = vector>; #define rep(i, n) for (int i = 0; i < (n); i++) #define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--) #define all(x) begin(x), end(x) constexpr char ln = '\n'; istream& operator>>(istream& is, __int128_t& x) { x = 0; string s; is >> s; int n = int(s.size()), it = 0; if (s[0] == '-') it++; for (; it < n; it++) x = (x * 10 + s[it] - '0'); if (s[0] == '-') x = -x; return is; } ostream& operator<<(ostream& os, __int128_t x) { if (x == 0) return os << 0; if (x < 0) os << '-', x = -x; deque deq; while (x) deq.emplace_front(x % 10), x /= 10; for (int e : deq) os << e; return os; } template ostream& operator<<(ostream& os, const pair& p) { return os << "(" << p.first << ", " << p.second << ")"; } template ostream& operator<<(ostream& os, const vector& v) { os << "{"; for (int i = 0; i < int(v.size()); i++) { if (i) os << ", "; os << v[i]; } return os << "}"; } template inline int SZ(const Container& v) { return int(v.size()); } template inline void UNIQUE(vector& v) { v.erase(unique(v.begin(), v.end()), v.end()); } template inline bool chmax(T1& a, T2 b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(T1& a, T2 b) { if (a > b) { a = b; return true; } return false; } inline int topbit(ull x) { return x == 0 ? -1 : 63 - __builtin_clzll(x); } inline int botbit(ull x) { return x == 0 ? 64 : __builtin_ctzll(x); } inline int popcount(ull x) { return __builtin_popcountll(x); } inline int kthbit(ull x, int k) { return (x >> k) & 1; } inline constexpr long long TEN(int x) { return x == 0 ? 1 : TEN(x-1) * 10; } template inline T ABS(T x) { return max(x, -x); } const string YESNO[2] = {"NO", "YES"}; const string YesNo[2] = {"No", "Yes"}; const string yesno[2] = {"no", "yes"}; inline void YES(bool t = 1) { cout << YESNO[t] << "\n"; } inline void Yes(bool t = 1) { cout << YesNo[t] << "\n"; } inline void yes(bool t = 1) { cout << yesno[t] << "\n"; } inline void print() { cout << "\n"; } template inline void print(const vector& v) { for (auto it = begin(v); it != end(v); ++it) { if (it != begin(v)) cout << " "; cout << *it; } print(); } template inline void print(const T& x, const Args& ... args) { cout << x << " "; print(args...); } #ifdef MINATO_LOCAL inline void debug_out() { cerr << endl; } template inline void debug_out(const T& x, const Args& ... args) { cerr << " " << x; debug_out(args...); } #define debug(...) cerr << __LINE__ << " : [" << #__VA_ARGS__ << "] =", debug_out(__VA_ARGS__) #else #define debug(...) (void(0)) #endif struct fast_ios { fast_ios() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); cerr << fixed << setprecision(7); }; } fast_ios_; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include #include #include #include #include #ifdef _MSC_VER #include #endif namespace atcoder { namespace internal { int ceil_pow2(int n) { int x = 0; while ((1U << x) < (unsigned int)(n)) x++; return x; } int bsf(unsigned int n) { #ifdef _MSC_VER unsigned long index; _BitScanForward(&index, n); return index; #else return __builtin_ctz(n); #endif } } // namespace internal } // namespace atcoder #include #include #include #ifdef _MSC_VER #include #endif #include #ifdef _MSC_VER #include #endif namespace atcoder { namespace internal { constexpr long long safe_mod(long long x, long long m) { x %= m; if (x < 0) x += m; return x; } struct barrett { unsigned int _m; unsigned long long im; barrett(unsigned int m) : _m(m), im((unsigned long long)(-1) / m + 1) {} unsigned int umod() const { return _m; } unsigned int mul(unsigned int a, unsigned int b) const { unsigned long long z = a; z *= b; #ifdef _MSC_VER unsigned long long x; _umul128(z, im, &x); #else unsigned long long x = (unsigned long long)(((unsigned __int128)(z)*im) >> 64); #endif unsigned int v = (unsigned int)(z - x * _m); if (_m <= v) v += _m; return v; } }; constexpr long long pow_mod_constexpr(long long x, long long n, int m) { if (m == 1) return 0; unsigned int _m = (unsigned int)(m); unsigned long long r = 1; unsigned long long y = safe_mod(x, m); while (n) { if (n & 1) r = (r * y) % _m; y = (y * y) % _m; n >>= 1; } return r; } constexpr bool is_prime_constexpr(int n) { if (n <= 1) return false; if (n == 2 || n == 7 || n == 61) return true; if (n % 2 == 0) return false; long long d = n - 1; while (d % 2 == 0) d /= 2; constexpr long long bases[3] = {2, 7, 61}; for (long long a : bases) { long long t = d; long long y = pow_mod_constexpr(a, t, n); while (t != n - 1 && y != 1 && y != n - 1) { y = y * y % n; t <<= 1; } if (y != n - 1 && t % 2 == 0) { return false; } } return true; } template constexpr bool is_prime = is_prime_constexpr(n); constexpr std::pair inv_gcd(long long a, long long b) { a = safe_mod(a, b); if (a == 0) return {b, 0}; long long s = b, t = a; long long m0 = 0, m1 = 1; while (t) { long long u = s / t; s -= t * u; m0 -= m1 * u; // |m1 * u| <= |m1| * s <= b auto tmp = s; s = t; t = tmp; tmp = m0; m0 = m1; m1 = tmp; } if (m0 < 0) m0 += b / s; return {s, m0}; } constexpr int primitive_root_constexpr(int m) { if (m == 2) return 1; if (m == 167772161) return 3; if (m == 469762049) return 3; if (m == 754974721) return 11; if (m == 998244353) return 3; int divs[20] = {}; divs[0] = 2; int cnt = 1; int x = (m - 1) / 2; while (x % 2 == 0) x /= 2; for (int i = 3; (long long)(i)*i <= x; i += 2) { if (x % i == 0) { divs[cnt++] = i; while (x % i == 0) { x /= i; } } } if (x > 1) { divs[cnt++] = x; } for (int g = 2;; g++) { bool ok = true; for (int i = 0; i < cnt; i++) { if (pow_mod_constexpr(g, (m - 1) / divs[i], m) == 1) { ok = false; break; } } if (ok) return g; } } template constexpr int primitive_root = primitive_root_constexpr(m); } // namespace internal } // namespace atcoder #include #include #include namespace atcoder { namespace internal { #ifndef _MSC_VER template using is_signed_int128 = typename std::conditional::value || std::is_same::value, std::true_type, std::false_type>::type; template using is_unsigned_int128 = typename std::conditional::value || std::is_same::value, std::true_type, std::false_type>::type; template using make_unsigned_int128 = typename std::conditional::value, __uint128_t, unsigned __int128>; template using is_integral = typename std::conditional::value || is_signed_int128::value || is_unsigned_int128::value, std::true_type, std::false_type>::type; template using is_signed_int = typename std::conditional<(is_integral::value && std::is_signed::value) || is_signed_int128::value, std::true_type, std::false_type>::type; template using is_unsigned_int = typename std::conditional<(is_integral::value && std::is_unsigned::value) || is_unsigned_int128::value, std::true_type, std::false_type>::type; template using to_unsigned = typename std::conditional< is_signed_int128::value, make_unsigned_int128, typename std::conditional::value, std::make_unsigned, std::common_type>::type>::type; #else template using is_integral = typename std::is_integral; template using is_signed_int = typename std::conditional::value && std::is_signed::value, std::true_type, std::false_type>::type; template using is_unsigned_int = typename std::conditional::value && std::is_unsigned::value, std::true_type, std::false_type>::type; template using to_unsigned = typename std::conditional::value, std::make_unsigned, std::common_type>::type; #endif template using is_signed_int_t = std::enable_if_t::value>; template using is_unsigned_int_t = std::enable_if_t::value>; template using to_unsigned_t = typename to_unsigned::type; } // namespace internal } // namespace atcoder namespace atcoder { namespace internal { struct modint_base {}; struct static_modint_base : modint_base {}; template using is_modint = std::is_base_of; template using is_modint_t = std::enable_if_t::value>; } // namespace internal template * = nullptr> struct static_modint : internal::static_modint_base { using mint = static_modint; public: static constexpr int mod() { return m; } static mint raw(int v) { mint x; x._v = v; return x; } static_modint() : _v(0) {} template * = nullptr> static_modint(T v) { long long x = (long long)(v % (long long)(umod())); if (x < 0) x += umod(); _v = (unsigned int)(x); } template * = nullptr> static_modint(T v) { _v = (unsigned int)(v % umod()); } unsigned int val() const { return _v; } mint& operator++() { _v++; if (_v == umod()) _v = 0; return *this; } mint& operator--() { if (_v == 0) _v = umod(); _v--; return *this; } mint operator++(int) { mint result = *this; ++*this; return result; } mint operator--(int) { mint result = *this; --*this; return result; } mint& operator+=(const mint& rhs) { _v += rhs._v; if (_v >= umod()) _v -= umod(); return *this; } mint& operator-=(const mint& rhs) { _v -= rhs._v; if (_v >= umod()) _v += umod(); return *this; } mint& operator*=(const mint& rhs) { unsigned long long z = _v; z *= rhs._v; _v = (unsigned int)(z % umod()); return *this; } mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); } mint operator+() const { return *this; } mint operator-() const { return mint() - *this; } mint pow(long long n) const { assert(0 <= n); mint x = *this, r = 1; while (n) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; } mint inv() const { if (prime) { assert(_v); return pow(umod() - 2); } else { auto eg = internal::inv_gcd(_v, m); assert(eg.first == 1); return eg.second; } } friend mint operator+(const mint& lhs, const mint& rhs) { return mint(lhs) += rhs; } friend mint operator-(const mint& lhs, const mint& rhs) { return mint(lhs) -= rhs; } friend mint operator*(const mint& lhs, const mint& rhs) { return mint(lhs) *= rhs; } friend mint operator/(const mint& lhs, const mint& rhs) { return mint(lhs) /= rhs; } friend bool operator==(const mint& lhs, const mint& rhs) { return lhs._v == rhs._v; } friend bool operator!=(const mint& lhs, const mint& rhs) { return lhs._v != rhs._v; } private: unsigned int _v; static constexpr unsigned int umod() { return m; } static constexpr bool prime = internal::is_prime; }; template struct dynamic_modint : internal::modint_base { using mint = dynamic_modint; public: static int mod() { return (int)(bt.umod()); } static void set_mod(int m) { assert(1 <= m); bt = internal::barrett(m); } static mint raw(int v) { mint x; x._v = v; return x; } dynamic_modint() : _v(0) {} template * = nullptr> dynamic_modint(T v) { long long x = (long long)(v % (long long)(mod())); if (x < 0) x += mod(); _v = (unsigned int)(x); } template * = nullptr> dynamic_modint(T v) { _v = (unsigned int)(v % mod()); } unsigned int val() const { return _v; } mint& operator++() { _v++; if (_v == umod()) _v = 0; return *this; } mint& operator--() { if (_v == 0) _v = umod(); _v--; return *this; } mint operator++(int) { mint result = *this; ++*this; return result; } mint operator--(int) { mint result = *this; --*this; return result; } mint& operator+=(const mint& rhs) { _v += rhs._v; if (_v >= umod()) _v -= umod(); return *this; } mint& operator-=(const mint& rhs) { _v += mod() - rhs._v; if (_v >= umod()) _v -= umod(); return *this; } mint& operator*=(const mint& rhs) { _v = bt.mul(_v, rhs._v); return *this; } mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); } mint operator+() const { return *this; } mint operator-() const { return mint() - *this; } mint pow(long long n) const { assert(0 <= n); mint x = *this, r = 1; while (n) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; } mint inv() const { auto eg = internal::inv_gcd(_v, mod()); assert(eg.first == 1); return eg.second; } friend mint operator+(const mint& lhs, const mint& rhs) { return mint(lhs) += rhs; } friend mint operator-(const mint& lhs, const mint& rhs) { return mint(lhs) -= rhs; } friend mint operator*(const mint& lhs, const mint& rhs) { return mint(lhs) *= rhs; } friend mint operator/(const mint& lhs, const mint& rhs) { return mint(lhs) /= rhs; } friend bool operator==(const mint& lhs, const mint& rhs) { return lhs._v == rhs._v; } friend bool operator!=(const mint& lhs, const mint& rhs) { return lhs._v != rhs._v; } private: unsigned int _v; static internal::barrett bt; static unsigned int umod() { return bt.umod(); } }; template internal::barrett dynamic_modint::bt = 998244353; using modint998244353 = static_modint<998244353>; using modint1000000007 = static_modint<1000000007>; using modint = dynamic_modint<-1>; namespace internal { template using is_static_modint = std::is_base_of; template using is_static_modint_t = std::enable_if_t::value>; template struct is_dynamic_modint : public std::false_type {}; template struct is_dynamic_modint> : public std::true_type {}; template using is_dynamic_modint_t = std::enable_if_t::value>; } // namespace internal } // namespace atcoder namespace atcoder { namespace internal { template * = nullptr> void butterfly(std::vector& a) { static constexpr int g = internal::primitive_root; int n = int(a.size()); int h = internal::ceil_pow2(n); static bool first = true; static mint sum_e[30]; // sum_e[i] = ies[0] * ... * ies[i - 1] * es[i] if (first) { first = false; mint es[30], ies[30]; // es[i]^(2^(2+i)) == 1 int cnt2 = bsf(mint::mod() - 1); mint e = mint(g).pow((mint::mod() - 1) >> cnt2), ie = e.inv(); for (int i = cnt2; i >= 2; i--) { es[i - 2] = e; ies[i - 2] = ie; e *= e; ie *= ie; } mint now = 1; for (int i = 0; i <= cnt2 - 2; i++) { sum_e[i] = es[i] * now; now *= ies[i]; } } for (int ph = 1; ph <= h; ph++) { int w = 1 << (ph - 1), p = 1 << (h - ph); mint now = 1; for (int s = 0; s < w; s++) { int offset = s << (h - ph + 1); for (int i = 0; i < p; i++) { auto l = a[i + offset]; auto r = a[i + offset + p] * now; a[i + offset] = l + r; a[i + offset + p] = l - r; } now *= sum_e[bsf(~(unsigned int)(s))]; } } } template * = nullptr> void butterfly_inv(std::vector& a) { static constexpr int g = internal::primitive_root; int n = int(a.size()); int h = internal::ceil_pow2(n); static bool first = true; static mint sum_ie[30]; // sum_ie[i] = es[0] * ... * es[i - 1] * ies[i] if (first) { first = false; mint es[30], ies[30]; // es[i]^(2^(2+i)) == 1 int cnt2 = bsf(mint::mod() - 1); mint e = mint(g).pow((mint::mod() - 1) >> cnt2), ie = e.inv(); for (int i = cnt2; i >= 2; i--) { es[i - 2] = e; ies[i - 2] = ie; e *= e; ie *= ie; } mint now = 1; for (int i = 0; i <= cnt2 - 2; i++) { sum_ie[i] = ies[i] * now; now *= es[i]; } } for (int ph = h; ph >= 1; ph--) { int w = 1 << (ph - 1), p = 1 << (h - ph); mint inow = 1; for (int s = 0; s < w; s++) { int offset = s << (h - ph + 1); for (int i = 0; i < p; i++) { auto l = a[i + offset]; auto r = a[i + offset + p]; a[i + offset] = l + r; a[i + offset + p] = (unsigned long long)(mint::mod() + l.val() - r.val()) * inow.val(); } inow *= sum_ie[bsf(~(unsigned int)(s))]; } } } } // namespace internal template * = nullptr> std::vector convolution(std::vector a, std::vector b) { int n = int(a.size()), m = int(b.size()); if (!n || !m) return {}; if (std::min(n, m) <= 60) { if (n < m) { std::swap(n, m); std::swap(a, b); } std::vector ans(n + m - 1); for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { ans[i + j] += a[i] * b[j]; } } return ans; } int z = 1 << internal::ceil_pow2(n + m - 1); a.resize(z); internal::butterfly(a); b.resize(z); internal::butterfly(b); for (int i = 0; i < z; i++) { a[i] *= b[i]; } internal::butterfly_inv(a); a.resize(n + m - 1); mint iz = mint(z).inv(); for (int i = 0; i < n + m - 1; i++) a[i] *= iz; return a; } template ::value>* = nullptr> std::vector convolution(const std::vector& a, const std::vector& b) { int n = int(a.size()), m = int(b.size()); if (!n || !m) return {}; using mint = static_modint; std::vector a2(n), b2(m); for (int i = 0; i < n; i++) { a2[i] = mint(a[i]); } for (int i = 0; i < m; i++) { b2[i] = mint(b[i]); } auto c2 = convolution(move(a2), move(b2)); std::vector c(n + m - 1); for (int i = 0; i < n + m - 1; i++) { c[i] = c2[i].val(); } return c; } std::vector convolution_ll(const std::vector& a, const std::vector& b) { int n = int(a.size()), m = int(b.size()); if (!n || !m) return {}; static constexpr unsigned long long MOD1 = 754974721; // 2^24 static constexpr unsigned long long MOD2 = 167772161; // 2^25 static constexpr unsigned long long MOD3 = 469762049; // 2^26 static constexpr unsigned long long M2M3 = MOD2 * MOD3; static constexpr unsigned long long M1M3 = MOD1 * MOD3; static constexpr unsigned long long M1M2 = MOD1 * MOD2; static constexpr unsigned long long M1M2M3 = MOD1 * MOD2 * MOD3; static constexpr unsigned long long i1 = internal::inv_gcd(MOD2 * MOD3, MOD1).second; static constexpr unsigned long long i2 = internal::inv_gcd(MOD1 * MOD3, MOD2).second; static constexpr unsigned long long i3 = internal::inv_gcd(MOD1 * MOD2, MOD3).second; auto c1 = convolution(a, b); auto c2 = convolution(a, b); auto c3 = convolution(a, b); std::vector c(n + m - 1); for (int i = 0; i < n + m - 1; i++) { unsigned long long x = 0; x += (c1[i] * i1) % MOD1 * M2M3; x += (c2[i] * i2) % MOD2 * M1M3; x += (c3[i] * i3) % MOD3 * M1M2; long long diff = c1[i] - internal::safe_mod((long long)(x), (long long)(MOD1)); if (diff < 0) diff += MOD1; static constexpr unsigned long long offset[5] = { 0, 0, M1M2M3, 2 * M1M2M3, 3 * M1M2M3}; x -= offset[diff % 5]; c[i] = x; } return c; } } // namespace atcoder using namespace atcoder; //using mint = modint998244353; using mint = modint1000000007; //using mint = modint; istream& operator>>(istream& is, modint998244353& M) { long long x; is >> x; M = x; return is; } ostream& operator<<(ostream& os, const modint998244353& M) { return os << M.val(); } istream& operator>>(istream& is, modint1000000007& M) { long long x; is >> x; M = x; return is; } ostream& operator<<(ostream& os, const modint1000000007& M) { return os << M.val(); } template istream& operator>>(istream& is, static_modint& M) { long long x; is >> x; M = x; return is; } template ostream& operator<<(ostream& os, const static_modint& M) { return os << M.val(); } istream& operator>>(istream& is, modint& M) { long long x; is >> x; M = x; return is; } ostream& operator<<(ostream& os, const modint& M) { return os << M.val(); } vector multiply(vector a, vector b) { return convolution(a,b); } vector multiply_naive(vector a, vector b) { int n = int(a.size()), m = int(b.size()); if (!n or !m) return {}; vector ret(n + m - 1); for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { ret[i + j] += a[i] * b[j]; } } return ret; } //59501818244292734739283969=5.95*10^25 までの値を正しく計算 //最終的な列の大きさが 2^24 までなら動く //最終的な列の大きさが 2^20 以下のときは,下の 3 つの素数を使ったほうが速い namespace arbitrary_convolution { constexpr int m0 = 167772161; constexpr int m1 = 469762049; constexpr int m2 = 754974721; constexpr int r01 = 104391568; // mint1(m0).inv() constexpr int r02 = 323560596; // mint2(m0).inv() constexpr int r12 = 399692502; // mint2(m1).inv() // constexpr int m0 = 1045430273; // constexpr int m1 = 1051721729; // constexpr int m2 = 1053818881; // constexpr int r01 = 175287122; // mint1(m0).inv() // constexpr int r02 = 395182206; // mint2(m0).inv() // constexpr int r12 = 526909943; // mint2(m1).inv() constexpr int r02r12 = (long long)(r02) * r12 % m2; constexpr long long w1 = m0; constexpr long long w2 = (long long)(m0) * m1; template vector multiply(const vector& a, const vector& b, int mod) { int n = int(a.size()), m = int(b.size()); vector v0 = convolution(a, b); vector v1 = convolution(a, b); vector v2 = convolution(a, b); vector ret(n + m - 1); const int W1 = w1 % mod; const int W2 = w2 % mod; for (int i = 0; i < n + m - 1; i++) { int n1 = v1[i], n2 = v2[i], x = v0[i]; int y = (long long)(n1 + m1 - x) * r01 % m1; int z = ((long long)(n2 + m2 - x) * r02r12 + (long long)(m2 - y) * r12) % m2; ret[i] = ((long long)(x) + (long long)(y) * W1 + (long long)(z) * W2) % mod; } return ret; } template vector multiply(vector a, vector b) { int n = int(a.size()), m = int(b.size()); if (!n or !m) return {}; if (min(n,m) < 128) { if (n < m) { swap(n, m); swap(a, b); } vector ret(n + m - 1); for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { ret[i + j] += a[i] * b[j]; } } return ret; } vector a_(n), b_(m); for (int i = 0; i < n; i++) a_[i] = a[i].val(); for (int i = 0; i < m; i++) b_[i] = b[i].val(); vector c = multiply(a_, b_, D::mod()); vector ret(n + m - 1); for (int i = 0; i < n + m - 1; i++) ret[i] = D::raw(c[i]); return ret; } } template (*op)(vector, vector)> struct FormalPowerSeries { using Poly = FormalPowerSeries; vector v; FormalPowerSeries(const vector& v_ = {}) : v(v_) { shrink(); } void shrink() { while (v.size() && v.back() == 0) v.pop_back(); } int size() const { return int(v.size()); } D freq(int p) const { return (p < size()) ? v[p] : D(0); } Poly operator+(const Poly& r) const { int n = max(size(), r.size()); vector res(n); for (int i = 0; i < n; i++) res[i] = freq(i) + r.freq(i); return res; } Poly operator-(const Poly& r) const { int n = max(size(), r.size()); vector res(n); for (int i = 0; i < n; i++) res[i] = freq(i) - r.freq(i); return res; } Poly operator*(const Poly& r) const { return op(v, r.v); } Poly operator*(const D& r) const { int n = size(); vector res(n); for (int i = 0; i < n; i++) res[i] = v[i] * r; return res; } Poly operator*(const vector>& r) const { assert(!r.empty()); int n = size(); int m = r.back().first; vector res(n + m); for (int i = 0; i < n; i++) { for (auto e : r) { res[i + e.first] += v[i] * e.second; } } return res; } Poly operator/(const D& r) const { return *this * r.inv(); } Poly operator/(const Poly& r) const { if (size() < r.size()) return {{}}; int n = size() - r.size() + 1; return (rev().pre(n) * r.rev().inv(n)).pre(n).rev(n); } Poly operator/(const vector>& r) const { assert(!r.empty()); int n = size(); auto [d, c] = r.front(); assert(d == 0 && c != D(0)); D ic = D(1) / c; vector res(n); for (int i = 0; i < n; i++) { for (auto& e : r) { if (e.first and e.first <= i) { res[i] -= res[i - e.first] * e.second; } } res[i] += v[i]; res[i] *= ic; } return res; } Poly operator%(const Poly& r) const { return *this - *this / r * r; } Poly operator<<(int s) const { vector res(size() + s); for (int i = 0; i < size(); i++) res[i + s] = v[i]; return res; } Poly operator>>(int s) const { if (size() <= s) return Poly(); vector res(size() - s); for (int i = 0; i < size() - s; i++) res[i] = v[i + s]; return res; } Poly& operator+=(const Poly& r) { return *this = *this + r; } Poly& operator-=(const Poly& r) { return *this = *this - r; } Poly& operator*=(const Poly& r) { return *this = *this * r; } Poly& operator*=(const D& r) { return *this = *this * r; } Poly& operator*=(const vector>& r) { return *this = *this * r; } Poly& operator/=(const Poly& r) { return *this = *this / r; } Poly& operator/=(const D &r) {return *this = *this/r;} Poly& operator/=(const vector>& r) { return *this = *this / r; } Poly& operator%=(const Poly& r) { return *this = *this % r; } Poly& operator<<=(const size_t& n) { return *this = *this << n; } Poly& operator>>=(const size_t& n) { return *this = *this >> n; } Poly mul(int d, const D& c) const { vector res(size() + d); for (int i = 0; i < size(); i++) { res[i] += v[i]; res[i+d] += v[i] * c; } return res; } Poly div(int d, const D& c) const { vector res(size()); for (int i = 0; i < size(); i++) { res[i] = v[i]; if (i >= d) res[i] -= res[i - d] * c; } return res; } Poly pre(int le) const { return {{v.begin(), v.begin() + min(size(), le)}}; } Poly rev(int n = -1) const { vector res = v; if (n != -1) res.resize(n); reverse(res.begin(), res.end()); return res; } Poly diff() const { vector res(max(0, size() - 1)); for (int i = 1; i < size(); i++) res[i - 1] = freq(i) * i; return res; } Poly inte() const { vector res(size() + 1); for (int i = 0; i < size(); i++) res[i + 1] = freq(i) / (i + 1); return res; } // f * f.inv() = 1 + g(x)x^m Poly inv(int m) const { Poly res = Poly({D(1) / freq(0)}); for (int i = 1; i < m; i *= 2) { res = (res * D(2) - res * res * pre(2 * i)).pre(2 * i); } return res.pre(m); } Poly exp(int n) const { assert(freq(0) == 0); Poly f({1}), g({1}); for (int i = 1; i < n; i *= 2) { g = (g * 2 - f * g * g).pre(i); Poly q = diff().pre(i - 1); Poly w = (q + g * (f.diff() - f * q)).pre(2 * i - 1); f = (f + f * (*this - w.inte()).pre(2 * i)).pre(2 * i); } return f.pre(n); } Poly log(int n) const { assert(freq(0) == 1); auto f = pre(n); return (f.diff() * f.inv(n - 1)).pre(n - 1).inte(); } Poly sqrt(int n) const { assert(freq(0) == 1); Poly f = pre(n + 1); Poly g({1}); for (int i = 1; i < n; i *= 2) { g = (g + f.pre(2 * i) * g.inv(2 * i)) / 2; } return g.pre(n + 1); } Poly pow_mod(ll n, const Poly& mod) { Poly x = *this, r = {{1}}; while (n) { if (n & 1) r = r * x % mod; x = x * x % mod; n >>= 1; } return r; } friend ostream& operator<<(ostream& os, const Poly& p) { if (p.size() == 0) return os << "0"; for (auto i = 0; i < p.size(); i++) { if (p.v[i] != 0) { os << p.v[i] << " x^" << i; if (i != p.size() - 1) os << " + "; } } return os; } }; using Poly = FormalPowerSeries; int main() { int K,N; cin >> K >> N; Poly f; f.v.assign(K+1,0); f.v[0] = 1; rep(i,N) { int x; cin >> x; if (x <= K) f.v[x]--; } f = f.inv(K+1); cout << f.freq(K) << ln; }