#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
using namespace std;
vector<vector<int>> vec(1000010);
bool bo[1000010] = { false };
int main() {
	long long n;
	cin >> n;
	for (int i = 0; i < n - 1; i++) {
		int a, b;
		cin >> a >> b;
		vec[a].emplace_back(b);
		bo[b] = true;
	}
	queue<pair<int, long long>> que;
	for (int i = 1; i <= n; i++) {
		if (!bo[i]) {
			que.push(make_pair(i, 0));
		}
	}
	long long ans = 0;
	while (!que.empty()) {
		pair<int, long long> p;
		p = que.front();
		ans += p.second * (p.second + 1) / 2;
		ans %= 1000000007;
		for (int i = 0; i < vec[p.first].size(); i++) {
			que.push(make_pair(vec[p.first][i], p.second + 1));
		}
		que.pop();
	}
	cout << ans << endl;
}