#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
typedef long long int ll;
typedef long double ld;
#define FOR(i,l,r) for(ll i=l;i<r;i++)
#define REP(i,n) FOR(i,0,n)
#define RFOR(i,l,r) for(ll i=r-1;i>=l;i--)
#define RREP(i,n) RFOR(i,0,n)
#define ALL(x) x.begin(),x.end()
#define PA pair<ll,ll>
#define F first
#define S second
#define BS(A,x) binary_search(ALL(A),x)
#define LB(A,x) (ll)(lower_bound(ALL(A),x)-A.begin())
#define UB(A,x) (ll)(upper_bound(ALL(A),x)-A.begin())
#define COU(A,x) (UB(A,x)-LB(A,x))
#define sz(c) ((ll)(c).size())
//#include<boost/multiprecision/cpp_int.hpp>
//namespace mp=boost::multiprecision;
//using Bint=mp::cpp_int;
template<typename T>using min_priority_queue=priority_queue<T,vector<T>,greater<T>>;
template<typename T1,typename T2>ostream&operator<<(ostream&os,pair<T1,T2>&p){os<<p.F<<" "<<p.S;return os;}
template<typename T1,typename T2>istream&operator>>(istream&is,pair<T1,T2>&p){is>>p.F>>p.S;return is;}
template<typename T>ostream&operator<<(ostream&os,vector<T>&v){REP(i,sz(v))os<<v[i]<<(i+1!=sz(v)?" ":"");return os;}
template<typename T>istream&operator>>(istream&is,vector<T>&v){for(T&in:v)is>>in;return is;}
template<class T>bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T&a,T b){if(b<a){a=b;return 1;}return 0;}
ld dist(ld x1,ld y1,ld x2,ld y2){return sqrtl((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));}
using mint=modint1000000007;
//using mint=modint998244353;
const ll mod=1000000007;
//const ll mod=998244353;
//using mint=modint;
ostream&operator<<(ostream&os,mint&a){os<<a.val();return os;}
int main(){
  ll N;cin>>N;
  vector<vector<ll>>E(N),R(N);
  vector<ll>cnt(N);
  REP(i,N-1){
    ll a,b;cin>>a>>b;a--;b--;
    E[a].emplace_back(b);
    R[b].emplace_back(a);
  }
  mint ans=0;
  ll r=0;while(sz(R[r]))r++;
  vector<ll>D(N,1e18);
  queue<ll>Q;Q.emplace(r);
  D[r]=1;
  while(sz(Q)){
      ll v=Q.front();Q.pop();
      for(auto u:E[v])if(chmin(D[u],D[v]+1))Q.emplace(u);
  }
  vector<ll>S(N,1);
  REP(i,N)cnt[i]=sz(E[i]);
  REP(i,N)if(!cnt[i])Q.emplace(i);
  while(sz(Q)){
    ll v=Q.front();Q.pop();
    for(auto u:R[v]){
      S[u]+=S[v];
      cnt[u]--;
      if(!cnt[u])Q.emplace(u);
    }
  }
  REP(v,N)for(auto u:E[v]){
      if(D[u]>D[v])ans+=S[u]*D[v];
      else ans+=S[v]*D[u];
  }
  cout<<ans<<endl;
  return 0;
}