// includes {{{
#include<iostream>
#include<iomanip>
#include<algorithm>
#include<vector>
#include<stack>
#include<queue>
#include<map>
#include<set>
#include<tuple>
#include<cmath>
#include<random>
#include<cassert>
// #include<deque>
// #include<multiset>
// #include<bitset>
// #include<cstring>
// #include<bits/stdc++.h>
// }}}
using namespace std;
using ll = long long;

// #undef DEBUG
// #define DEBUG
// DEBUG {{{
#include <array>
#include <deque>
#include <iostream>
#include <list>
#include <queue>
#include <stack>
#include <tuple>
#include <valarray>
#include <vector>
// clang-format off
template<int n, class...T> typename enable_if<(n>=sizeof...(T))>::type _ot(ostream &, tuple<T...> const &){}
template<int n, class...T> typename enable_if<(n< sizeof...(T))>::type _ot(ostream & os, tuple<T...> const & t){ os << (n==0?"":", ") << get<n>(t); _ot<n+1>(os, t); }
template<class...T> ostream & operator<<(ostream &o, tuple<T...> const &t){ o << "("; _ot<0>(o, t); o << ")"; return o; }
template<class T, class U> ostream & operator<<(ostream &o, pair<T, U> const &p) { o << "(" << p.first << ", " << p.second << ")"; return o; }
template < class T > ostream &operator<<(ostream &o, const stack<T> &a) { o << "{"; for(auto tmp = a; tmp.size(); tmp.pop()) o << (a.size() == tmp.size() ? "" : ", ") << tmp.top(); o << "}"; return o; }
template <class T, class Container, class Compare > ostream &operator<<(ostream &os, priority_queue<T, Container, Compare> a) { os << "{ (top) "; while(a.size()) os << a.top() << (a.size() == 1 ? "" : ", "), a.pop(); os << " }"; return os; }
template <class T, class Container > ostream &operator<<(ostream &os, queue<T, Container> a) { os << "{ "; while(a.size()) os << a.front() << (a.size() == 1 ? "" : ", "), a.pop(); os << " }"; return os; }
#ifdef DEBUG
#if !defined(DEBUG_OUT)
#define DEBUG_OUT cerr
#endif
#if !defined(DEBUG_LEFT)
#define DEBUG_LEFT "\e[1;36m"
#endif
#if !defined(DEBUG_RIGHT)
#define DEBUG_RIGHT ":\e[m"
#endif
#define dump(...) [&](){auto __debug_tap=make_tuple(__VA_ARGS__);DEBUG_OUT<<DEBUG_LEFT<<__LINE__ << DEBUG_RIGHT << " " <<#__VA_ARGS__<<" = "<<__debug_tap<<endl;}()
template < class T > inline void dump2D(T &d, size_t sizey, size_t sizex) { for(size_t i = 0; i < sizey; i++) { DEBUG_OUT << "\t"; for(size_t j = 0; j < sizex; j++) DEBUG_OUT << d[i][j] << (j + 1 == sizex ? "" : "\t"); DEBUG_OUT << endl; } }
template < class T, class = typename iterator_traits< decltype(begin(T())) >::value_type, class = typename enable_if<!is_same<T, string>::value>::type > ostream &operator<<(ostream &o, const T &a) { o << "{"; for(auto ite = begin(a); ite != end(a); ++ite) o << (ite == begin(a) ? "" : ", ") << *ite; o << "}"; return o; }
#else
#define dump(...) (42)
#define dump2D(...) (42)
template < class T, class = typename iterator_traits< decltype(begin(T())) >::value_type, class = typename enable_if<!is_same<T, string>::value>::type > ostream &operator<<(ostream &o, const T &a) { for(auto ite = begin(a); ite != end(a); ++ite) o << (ite == begin(a) ? "" : " ") << *ite; return o; }
#endif
// clang-format on
// }}}

// WARN : use H with larger N
/// --- Modulo Factorial {{{ ///
template < int N, int mod = (int) 1e9 + 7 >
struct Factorial {
  constexpr ll extgcd(ll a, ll b, ll &x, ll &y) {
    ll d = 0;
    return b == 0 ? (x = 1, y = 0, a) : (d = extgcd(b, a % b, y, x), y -= a / b * x, d);
  }
  constexpr ll modinv(ll a) {
    ll x = 0, y = 0;
    extgcd(a, mod, x, y);
    return (x + mod) % mod;
  }
  int arr[N + 1], inv[N + 1];
  ll operator[](int i) const { return arr[i]; }
#if !defined(DEBUG)
  constexpr
#endif
    Factorial()
    : arr(), inv() {
      arr[0] = 1;
      for(int i = 1; i <= N; i++) {
        arr[i] = (ll) i * arr[i - 1] % mod;
      }
      inv[N] = modinv(arr[N]);
      for(int i = N - 1; i >= 0; i--) {
        inv[i] = (ll)(i + 1) * inv[i + 1] % mod;
      }
    }
  ll C(int n, int r) const {
    if(n < 0 || r < 0 || n < r) return 0;
    return (ll) arr[n] * inv[r] % mod * inv[n - r] % mod;
  }
  ll H(int n, int r) const { return C(n + r - 1, r); }
};
/// }}}--- ///

const int mod = 1e9 + 7;
const int N = 5000;
vector<int> g[N];
int n;

Factorial < N * 2, mod > fact;

// dp[i] = 今一番浅い連結成分の頂点数がi であるようなものの通り数 を辺の取り除き方すべてについて足したもの


vector<ll> dualFact(N * 2);

vector<ll> mrg2(vector<ll> a, vector<ll> b) {
  vector<ll> c(a.size() + b.size() - 1);
  for(int i = 0; i < a.size(); i++) for(int j = 0; j < b.size(); j++) {
    (c[i + j] += a[i] * b[j] % mod) %= mod;
  }
  return c;
}

vector<vector<ll>> mrg(vector<vector<ll>> a, vector<vector<ll>> b) {
  vector<vector<ll>> c(2, vector<ll>(a[0].size() + b[0].size() - 1));
  auto v = mrg2(a[0], b[0]);
  for(int i = 0; i < v.size(); i++) c[0][i] += v[i];
  v = mrg2(a[1], b[1]);
  for(int i = 0; i < v.size(); i++) c[0][i] += v[i];
  v = mrg2(a[1], b[0]);
  for(int i = 0; i < v.size(); i++) c[1][i] += v[i];
  v = mrg2(a[0], b[1]);
  for(int i = 0; i < v.size(); i++) c[1][i] += v[i];
  for(auto &el : c) for(auto &el2 : el) el2 %= mod;
  return c;
}

vector<vector<ll>> dfs(int i, int p) {
  vector<vector<ll>> v{
    {0, 1},
    {0, 0},
  }; // 一頂点分
  for(int j : g[i]) if(j != p) {
    auto w = dfs(j, i);
    ll x = 0, y = 0;
    for(int k = 1; k < w[0].size(); k++) (w[1][0] += w[0][k] * dualFact[k-1] % mod) %= mod;
    for(int k = 1; k < w[1].size(); k++) (w[0][0] += w[1][k] * dualFact[k-1] % mod) %= mod;
    v = mrg(v, w);
  }
  // dump(i, v);
  assert(v[0][0] == 0);
  assert(v[1][0] == 0);
  return v;
}

void init() {
  // only odd
  dualFact[1] = 1;
  for(int i = 3; i < dualFact.size(); i+=2) dualFact[i] = dualFact[i-2] * i % mod;
}

int main() {
  init();
  ios::sync_with_stdio(false), cin.tie(0);
  cin >> n;
  int a, b;
  for(int i = 0; i < n - 1; i++) {
    cin >> a >> b;
    a--; b--;
    g[a].emplace_back(b);
    g[b].emplace_back(a);
  }

  ll ans = 0;
  auto v = dfs(0, -1);

  dump(v);

  for(int i = 1; i < v[0].size(); i++) ans += v[0][i] * dualFact[i-1] % mod;
  for(int i = 1; i < v[1].size(); i++) ans += mod - v[1][i] * dualFact[i-1] % mod;
  ans %= mod;

  cout << ans << endl;
  return 0;
}


Measured memory_bytes: 2176