MOD = 10 ** 9 + 7
N = int(input())
E = [[] for _ in range(N)]
D = [0] * N
for _ in range(N - 1):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    E[a].append(b)
    D[b] += 1

ans = 0
Q = [D.index(0)]
Q2 = []
ans = 0
cnt = 0
cnt2 = 0
while Q:
    cnt2 += cnt
    cnt += 1
    ans += cnt2 * len(Q)
    ans %= MOD
    while Q:
        x = Q.pop()
        for y in E[x]:
            Q2.append(y)
    Q, Q2 = Q2, Q
print(ans)