#include using namespace std; using lint = long long int; using pint = pair; using plint = pair; struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_; #define ALL(x) (x).begin(), (x).end() #define SZ(x) ((lint)(x).size()) #define POW2(n) (1LL << (n)) #define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i=i##_begin_;i--) #define REP(i, n) FOR(i,0,n) #define IREP(i, n) IFOR(i,0,n) template void ndarray(vector &vec, int len) { vec.resize(len); } template void ndarray(vector &vec, int len, Args... args) { vec.resize(len); for (auto &v : vec) ndarray(v, args...); } template bool mmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; } template bool mmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; } template pair operator+(const pair &l, const pair &r) { return make_pair(l.first + r.first, l.second + r.second); } template pair operator-(const pair &l, const pair &r) { return make_pair(l.first - r.first, l.second - r.second); } template istream &operator>>(istream &is, vector &vec){ for (auto &v : vec) is >> v; return is; } ///// This part below is only for debug, not used ///// template ostream &operator<<(ostream &os, const vector &vec){ os << "["; for (auto v : vec) os << v << ","; os << "]"; return os; } template ostream &operator<<(ostream &os, const deque &vec){ os << "deq["; for (auto v : vec) os << v << ","; os << "]"; return os; } template ostream &operator<<(ostream &os, const set &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const unordered_set &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const multiset &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const unordered_multiset &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const pair &pa){ os << "(" << pa.first << "," << pa.second << ")"; return os; } template ostream &operator<<(ostream &os, const map &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; } template ostream &operator<<(ostream &os, const unordered_map &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; } #define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl; ///// END ///// /* #include #include #include using namespace __gnu_pbds; // find_by_order(), order_by_key() template using pbds_set = tree, rb_tree_tag, tree_order_statistics_node_update>; template using pbds_map = tree, rb_tree_tag, tree_order_statistics_node_update>; */ constexpr lint MOD = 1000000007; vector fac, facInv, inv; void facInit(int nmax) { fac = facInv = inv = vector(nmax + 1, 1); for (int i = 2; i <= nmax; i++) { fac[i] = fac[i-1] * i % MOD; inv[i] = MOD - inv[MOD%i] * (MOD/i) % MOD; facInv[i] = facInv[i-1] * inv[i] % MOD; } } lint nCr(int n, int r) { if (n= (int)fac.size()) facInit(n); return (fac[n] * facInv[r] % MOD) * facInv[n-r] % MOD; } lint nPr(int n, int r) { if (n= (int)fac.size()) facInit(n); return fac[n] * facInv[n-r] % MOD; } vector> e; int N; lint ret; void dfs(int now, int prv, int depth) { (ret += nCr(N, depth) * fac[depth - 1] % MOD * fac[N - depth]) %= MOD; for (auto nxt : e[now]) if (nxt != prv) dfs(nxt, now, depth + 1); } int main() { cin >> N; facInit(N); e.resize(N + 1); REP(_, N - 1) { int u, v; cin >> u >> v; e[u].insert(v); e[v].insert(u); } ret = 0; dfs(1, -1, 1); cout << ret << endl; }