from collections import deque
MOD = 10 ** 9 + 7

n = int(input())
root_cand = [True for _ in range(n)]
edges = [[] for _ in range(n)]
for _ in range(n - 1):
    a, b = map(int, input().split())
    edges[a - 1].append(b - 1)
    root_cand[b - 1] = False
root = root_cand.index(True)

ans = 0
queue = deque()
queue.append(root)
queue.append(0)
while queue:
    pos = queue.popleft()
    d = queue.popleft()
    ans += d * (d + 1) // 2
    ans %= MOD
    for n_pos in edges[pos]:
        queue.append(n_pos)
        queue.append(d + 1)
print(ans)