#include <bits/stdc++.h>

int ri() {
	int n;
	scanf("%d", &n);
	return n;
}

std::vector<std::vector<int> > hen;

int64_t res = 0;
void dfs(int i, int depth) {
	res += (int64_t) depth * (depth + 1) / 2;
	for (auto j : hen[i]) dfs(j, depth + 1);
}

int main() {
	int n = ri();
	hen.resize(n);
	std::vector<bool> used(n);
	for (int i = 1; i < n; i++) {
		int a = ri() - 1;
		int b = ri() - 1;
		hen[a].push_back(b);
		used[b] = true;
	}
	int root = std::find(used.begin(), used.end(), false) - used.begin();
	dfs(root, 0);
	printf("%d\n", (int) (res % 1000000007));
	
	return 0;
}