#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;

template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (ll i=(ll)from; i<(ll)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (int i=(int)N-1; i>=0; i--)

const ll MOD = pow(10,9)+7;
const ll LLINF = pow(2,61)-1;
const int INF = pow(2,30)-1;

vector<ll> fac;
void c_fac(int x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; }
ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { int d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; }
ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; }
ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }

vector<ll> score, sz;
vector<vector<ll>> adj;

void dfs(ll n) {
  for (auto x: adj[n]) {
    dfs(x);
    score[n] += score[x] + sz[x];
    sz[n] += sz[x];
  }
}

int main() {
  ll N; cin >> N;
  ll root = N*(N-1)/2;
  adj.resize(N);
  rep(i,N-1) {
    ll A, B; cin >> A >> B; A--; B--;
    adj[A].push_back(B);
    root -= B;
  }
  score.resize(N); sz.resize(N,1);
  dfs(root);
  // debug(all(score)); debug(all(sz));

  ll result = 0; for (auto x: score) result = (result+x)%MOD;
  cout << result << endl;
  return 0;
}