#include <cassert>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <limits.h>
#include <map>
#include <queue>
#include <set>
#include <string.h>
#include <vector>

using namespace std;
typedef long long ll;
typedef pair<int, int> Node;

const ll MOD = 1000000007;
const int MAX_N = 1000010;
vector<int> E[MAX_N];
int P[MAX_N];
int N;

int find_root(int v) {
  if (P[v] == -1) return v;
  return find_root(P[v]);
}

ll dfs(int v, int depth) {
  ll len = 0;

  for (int u : E[v]) {
    len += depth * (depth + 1) / 2;
    len %= MOD;
    len += dfs(u, depth + 1);
    len %= MOD;
  }

  return len;
}

int main() {
  memset(P, -1, sizeof(P));
  cin >> N;

  for (int i = 0; i < N - 1; ++i) {
    int a, b;
    cin >> a >> b;

    E[a].push_back(b);
    P[b] = a;
  }

  int root = find_root(1);
  ll ans = 0;
  // cout << dfs(root, 1) << endl;
  queue<Node> que;
  que.push(Node(root, 1));

  while (not que.empty()) {
    Node node = que.front();
    int v = node.first;
    int depth = node.second;
    que.pop();

    for (int u : E[v]) {
      ans += depth * (depth + 1) / 2;
      ans %= MOD;
      que.push(Node(u, depth + 1));
    }
  }

  cout << ans << endl;

  return 0;
}