import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
from collections import deque
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

class Graph(object):
	def __init__(self):
		self.graph = defaultdict(list)

	def __len__(self):
		return len(self.graph)

	def add_edge(self, a, b):
		self.graph[a].append(b)

class BFS(object):
	def __init__(self, graph, s, N):
		self.g = graph.graph
		self.Q = deque(); self.Q.append(s)
		self.dist = [INF] * N; self.dist[s] = 0
		while self.Q:
			v = self.Q.popleft()
			for i in self.g[v]:
				if self.dist[i] == INF:
					self.dist[i] = self.dist[v] + 1
					self.Q.append(i)

#処理内容
def main():
	N = int(input())
	Ein = [0] * N
	G = Graph()
	for i in range(N - 1):
		a, b = getlist()
		a -= 1; b -= 1
		G.add_edge(a, b)
		Ein[b] = 1

	s = None
	for i in range(N):
		if Ein[i] == 0:
			s = i
			break

	BF = BFS(G, s, N)
	dist = BF.dist
	ans = 0
	for i in range(N):
		v = dist[i]
		ans += int((v * (v + 1)) // 2)

	print(ans % con)


if __name__ == '__main__':
	main()