from collections import deque
N = int(input())
E = [[] for _ in range(N)]
par = [-1]*N
for _ in range(N-1):
    a,b = map(int, input().split())
    E[a-1].append(b-1)
    par[b-1] = a-1

for i in range(N):
    if par[i] == -1:
        root = i
        break

ans = 0
mod = 10**9+7
q = deque()
q.append(root)
while q:
    temp = q.pop()
    p = temp%N
    rnk = temp//N
    ans += rnk*(rnk+1)//2
    ans %= mod
    for v in E[p]:
        q.append((rnk+1)*N+v)

print(ans)