#include <iostream>
#include <vector>
#include <queue>
using namespace std;

const long long MOD = 1000000007;
struct d{
  int i,dep;
};

int main(){
  int n;cin>>n;
  vector<long long> A(n,-1);
  vector<int> C[n];
  for(int i = 0; n-1 > i; i++){
    int a,b;cin>>a>>b;
    A[--b] = --a;
    C[a].push_back(b);
  }
  int f = -1;
  for(int i = 0; n > i; i++){
    if(A[i] == -1)f = i;
  }

  queue<d> B;
  B.push({f,0});
  A[f] = 0;
  while(B.size()){
    auto x = B.front();B.pop();
    for(int i = 0; C[x.i].size() > i; i++){
      A[C[x.i][i]] = x.dep+1;
      B.push({C[x.i][i],x.dep+1});
    } 
  }
  long long ans = 0;
  for(int i = 0; n > i; i++){
    ans += A[i]*(A[i]+1)/2;
  }
  cout << ans%MOD << endl;
  

}