from collections import deque
import sys
input=sys.stdin.readline
MOD = 10**9 + 7
inpl = lambda: list(map(int,input().split()))
N = int(input())
children = [[] for _ in range(N)]
parent = [None] * N
for _ in range(N-1):
    A, B = inpl()
    A, B = A-1, B-1
    children[A].append(B)
    parent[B] = A
root = parent.index(None)
pool = deque([root, -1])
ans = 0
d, n = 0, 0
while pool:
    node = pool.popleft()
    if node < 0:
        ans += (n * d * (d+1) // 2) % MOD
        ans %= MOD
        n = 0
        d += 1
        if pool:
            pool.append(-1)
        else:
            break
    else:
        n += 1
        for c in children[node]:
            pool.append(c)
print(ans)