#define DEB
#include<bits/stdc++.h>
#define REP(i,m) for(int i=0;i<(m);++i)
#define REPN(i,m,in) for(int i=(in);i<(m);++i)
#define ALL(t) (t).begin(),(t).end()
#define CLR(a) memset((a),0,sizeof(a))
#define pb push_back
#define mp make_pair
#define fr first
#define sc second

using namespace std;


#ifdef DEB
#define dump(x)  cerr << #x << " = " << (x) << endl
#define prl cerr<<"called:"<< __LINE__<<endl
#define dumpR(x) cerr<<"\x1b[31m"<<#x<<" = " <<(x)<<"\x1b[39m"<<endl
#define dumpY(x) cerr<<"\x1b[33m"<<#x<<" = " <<(x)<<"\x1b[39m"<<endl
#define dumpG(x) cerr<<"\x1b[32m"<<#x<<" = " <<(x)<<"\x1b[39m"<<endl
template<class T> void debug(T a,T b){ for(;a!=b;++a) cerr<<*a<<' ';cerr<<endl;}
#else
#define dump(x) ;
#define dumpR(x) ;
#define dumpY(x) ;
#define dumpG(x) ;
#define prl ;
template<class T> void debug(T a,T b){ ;}
#endif

template<class T> bool chmin(T& a,const T& b) {
  if(a>b) {
    a=b;
    return true;
  }
  return false;
}
template<class T> bool chmax(T& a,const T& b) {
  if(a<b){
    a=b;
    return true;
  }
  return false;
}

typedef long long int lint;
typedef pair<int,int> pi;

namespace std{
  template<class S,class T>
  ostream &operator <<(ostream& out,const pair<S,T>& a){
    out<<'('<<a.fr<<','<<a.sc<<')';
    return out;
  }
}

//const int INF=5e8;
template<lint mod>
struct Int_{
  unsigned x;
  unsigned mpow(Int_ a,unsigned k){
    Int_ res=1;
    while(k){
      if(k&1) res=res*a;
      a=a*a;
      k>>=1;
    }
    return res.x;
  }
  unsigned inverse(Int_ a){
    return mpow(a,mod-2);
  }
  Int_(): x(0) { }
  Int_(long long sig) {
    int sigt=sig%mod;
    if(sigt<0) sigt+=mod;
    x=sigt;
  }
  unsigned get() const { return (unsigned)x; }
  
  Int_ &operator+=(Int_ that) { if((x += that.x) >= mod) x -= mod; return *this; }
  Int_ &operator-=(Int_ that) { if((x += mod - that.x) >= mod) x -= mod; return *this; }
  Int_ &operator*=(Int_ that) { x = (unsigned long long)x * that.x % mod; return *this; }
  Int_ &operator=(Int_ that) { x=that.x; return *this;}
  Int_ &operator/=(Int_ that) { x=(unsigned long long) x * inverse(that.x)%mod; return *this;}
  bool operator==(Int_ that) const { return x==that.x; }
  bool operator!=(Int_ that) const { return x!=that.x; }

  Int_ operator-() const { return Int_(0)-Int_(*this);}
  Int_ operator+(Int_ that) const { return Int_(*this) += that; }
  Int_ operator-(Int_ that) const { return Int_(*this) -= that; }
  Int_ operator*(Int_ that) const { return Int_(*this) *= that; }
  Int_ operator/(Int_ that) const { return Int_(*this) /= that; }
  Int_ inv(){
    return Int_(mpow(x,mod-2));
  }
};

namespace std{
  template<lint mod>
  ostream &operator <<(ostream& out,const Int_<mod>& a){
    out<<a.get();
    return out;
  }
  template<lint mod>
  istream &operator >>(istream& in,Int_<mod>& a){
    in>>a.x;
    return in;
  }
};

typedef Int_<1000000007> Int;

Int mpow(Int a,lint k){
  Int res=1;
  while(k){
    if(k&1) res=res*a;
    a=a*a;
    k>>=1;
  }
  return res;
}

const int M=10005;
Int fact[M+2],invf[M+2];
void prep(){
  fact[0]=invf[0]=1;
  REP(i,M){
    fact[i+1]=fact[i]*(i+1);
  }
  invf[M]=fact[M].inv();
  for(int i=M-1;i>=0;--i) invf[i]=invf[i+1]*(i+1);
}
Int C(int a,int b){
  if(a<0 || b<0 || a<b) return 0;
  return fact[a]*invf[a-b]*invf[b];
}

int n;
vector<int> g[5005];

Int dp[5005][5005];

void mrg(Int* ar,Int* br,int n,int m){
  Int cr[5005];
  CLR(cr);
  REP(i,n+1) REP(j,m+1){
    cr[i+j]+=ar[i]*br[j];
  }
  REP(i,n+m+1) ar[i]=cr[i];
}
Int pw2[5005];
Int calc(int n){
  assert(n%2==0);
  return C(n,n/2)*fact[n/2]*pw2[n/2];
}
int rec(int v,int p){
  dp[v][1]=1;
  int size=1;
  for(auto to:g[v]) if(to!=p){
    int csize=rec(to,v);
    mrg(dp[v],dp[to],size,csize);
    size+=csize;
  }
  {
    for(int i=size;i>0;--i) if(i%2==0 && dp[v][i].x){
      dp[v][0]-=dp[v][i]*calc(i);
    }
  }
  return size;
}
int main(){
  prep();
  pw2[0]=1;
  REP(i,5000) pw2[i+1]=pw2[i]/2;
  cin>>n;
  REP(i,n-1){
    int a,b;cin>>a>>b;--a;--b;
    g[a].pb(b);
    g[b].pb(a);
  }
  rec(0,-1);

  Int subt=dp[0][0];
  Int ans=calc(n);
  cout<<-subt<<endl;
  return 0;
}





Measured memory_bytes: 98816