#include #include #include #include #include #include #include static const int MOD = 1000000007; using ll = long long; using u32 = unsigned; using namespace std; template constexpr T INF = ::numeric_limits::max() / 32 * 15 + 208; template T pow_ (T x, T n, T M){ uint64_t u = 1, xx = x; while (n > 0){ if (n&1) u = u * xx % M; xx = xx * xx % M; n >>= 1; } return static_cast(u); }; template class Factorial { T mod; vector facts, factinv; public: Factorial(int n, T mod) : facts(static_cast(n+1)), factinv(static_cast(n+1)), mod(mod) { facts[0] = 1; for (int i = 1; i < n+1; ++i) facts[i] = facts[i-1]*i % mod; factinv[n] = pow_(facts[n], static_cast(mod - 2), static_cast(mod)); for (int i = n-1; i >= 0; --i) factinv[i] = factinv[i+1] * (i+1) % mod; } T fact(int k) const { return static_cast(facts[k]); } T operator[](const int &k) const { return static_cast(facts[k]); } T C(int p, int q) const { if(q < 0 || p < q) return 0; return static_cast(facts[p]* factinv[q] % mod * factinv[p-q] % mod); } T P(int p, int q) const { if(q < 0 || p < q) return 0; return static_cast((facts[p] * factinv[p-q]) % mod); } T H(int p, int q) const { if(p < 0 || q < 0) return 0; return static_cast(q == 0 ? 1 : C(p+q-1, q)); } }; template T extgcd(T a, T b, T &x ,T &y){ for (T u = y = 1, v = x = 0; a; ) { ll q = b/a; swap(x -= q*u, u); swap(y -= q*v, v); swap(b -= q*a, a); } return b; } template T mod_inv(T x, T m){ T s, t; extgcd(x, m, s, t); return (m+s)% m; } int main() { int n; cin >> n; if(n == 1) { cout << 1 << "\n"; return 0; } vector deg(n); for (int i = 0; i < n-1; ++i) { int a, b; cin >> a >> b; if(a > b) swap(a, b); deg[a-1]++; deg[b-1]++; } int k = 0; for (int i = 1; i < n; ++i) { if(deg[i] == 1) k++; } Factorial f(n, MOD); cout << ((f.C(n-2, k-1) * f.C(n-1, k-1)) % MOD)*mod_inv(k, MOD) % MOD << "\n"; return 0; }