#include #include #include //!===============================================================!// //! 88888888b dP .88888. a88888b. 888888ba !// //! 88 88 d8' '88 d8' '88 88 '8b !// //! a88aaaa dP. .dP d8888P 88 88 88 88 !// //! 88 '8bd8' 88 88 YP88 88 88 88 !// //! 88 .d88b. 88 Y8. .88 Y8. .88 88 .8P !// //! 88888888P dP' 'dP dP '88888' Y88888P' 8888888P !// //!===============================================================!// template constexpr std::pair extgcd(const T a, const T b) { if (b == 0) { return std::pair{1, 0}; } const auto p = extgcd(b, a % b); return {p.second, p.first - p.second * (a / b)}; } template constexpr T inverse(const T a, const T mod) { return (mod + extgcd((mod + a % mod) % mod, mod).first % mod) % mod; } using uint = unsigned int; using ll = long long; using ull = unsigned long long; //!========================================================!// //! 8888ba.88ba dP dP dP !// //! 88 '8b '8b 88 88 88 !// //! 88 88 88 .d8888b. .d888b88 88 88d888b. d8888P !// //! 88 88 88 88' '88 88' '88 88 88' '88 88 !// //! 88 88 88 88. .88 88. .88 88 88 88 88 !// //! dP dP dP '88888P' '88888P8 dP dP dP dP !// //!========================================================!// template class ModInt { private: uint v; static uint norm(const uint& x) { return x < mod ? x : x - mod; } static ModInt make(const uint& x) { ModInt m; return m.v = x, m; } static ModInt power(ModInt x, ll n) { ModInt ans = 1; for (; n; n >>= 1, x *= x) { if (n & 1) { ans *= x; } } return ans; } static ModInt inv(const ModInt& x) { return ModInt{inverse((ll)x.v, (ll)mod)}; } public: ModInt() : v{0} {} ModInt(const ll val) : v{norm(uint(val % (ll)mod + (ll)mod))} {} ModInt(const ModInt& n) : v{n()} {} explicit operator bool() const { return v != 0; } ModInt& operator=(const ModInt& n) { return v = n(), (*this); } ModInt& operator=(const ll val) { return v = norm(uint(val % (ll)mod + (ll)mod)), (*this); } ModInt operator+() const { return *this; } ModInt operator-() const { return make(norm(mod - v)); } ModInt operator+(const ModInt& val) const { return make(norm(v + val())); } ModInt operator-(const ModInt& val) const { return make(norm(v + mod - val())); } ModInt operator*(const ModInt& val) const { return make((uint)((ll)v * val() % (ll)mod)); } ModInt operator/(const ModInt& val) const { return *this * inv(val()); } ModInt& operator+=(const ModInt& val) { return *this = *this + val; } ModInt& operator-=(const ModInt& val) { return *this = *this - val; } ModInt& operator*=(const ModInt& val) { return *this = *this * val; } ModInt& operator/=(const ModInt& val) { return *this = *this / val; } ModInt operator+(const ll val) const { return ModInt{v + val}; } ModInt operator-(const ll val) const { return ModInt{v - val}; } ModInt operator*(const ll val) const { return ModInt{(ll)v * (val % mod)}; } ModInt operator/(const ll val) const { return ModInt{(ll)v * inv(val)}; } template ModInt operator^(const I n) const { return power(v, n); } ModInt& operator+=(const ll val) { return *this = *this + val; } ModInt& operator-=(const ll val) { return *this = *this - val; } ModInt& operator*=(const ll val) { return *this = *this * val; } ModInt& operator/=(const ll val) { return *this = *this / val; } template ModInt& operator^=(const I n) { return (*this) = ((*this) ^ n); } bool operator==(const ModInt& val) const { return v == val.v; } bool operator!=(const ModInt& val) const { return not(*this == val); } bool operator==(const ll val) const { return v == norm(uint((ll)mod + val % (ll)mod)); } bool operator!=(const ll val) const { return not(*this == val); } uint operator()() const { return v; } }; template inline ModInt operator+(const ll val, const ModInt& n) { return n + val; } template inline ModInt operator-(const ll val, const ModInt& n) { return ModInt{val - (ll)n()}; } template inline ModInt operator*(const ll val, const ModInt& n) { return n * val; } template inline ModInt operator/(const ll val, const ModInt& n) { return ModInt(val) / n; } template inline bool operator==(const ll val, const ModInt& n) { return n == val; } template inline bool operator!=(const ll val, const ModInt& n) { return not(val == n); } template inline std::istream& operator>>(std::istream& is, ModInt& n) { uint v; return is >> v, n = v, is; } template std::ostream& operator<<(std::ostream& os, const ModInt& n) { return (os << n()); } constexpr uint MOD = 1000000007; using mint = ModInt; int main() { std::cin.tie(nullptr); std::ios::sync_with_stdio(false); int N; std::cin >> N; std::vector> G(N); for (int i = 0; i < N - 1; i++) { int u, v; std::cin >> u >> v; u--, v--; G[u].push_back(v), G[v].push_back(u); } std::vector L(N + 2, 1), R(N + 2, 1); for (int i = 1; i <= N; i++) { L[i] = L[i - 1] * i; } for (int i = N; i >= 1; i--) { R[i] = R[i + 1] * i; } mint ans = 0; auto dfs = [&](auto&& self, const int s, const int p, const int d) -> void { ans += L[d - 1] * R[d + 1]; for (const int to : G[s]) { if (to == p) { continue; } self(self, to, s, d + 1); } }; dfs(dfs, 0, -1, 1); std::cout << ans << std::endl; return 0; }