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

ans = 0
mod = 10**9+7
d = deque()
root = roots.index(True)
d.append([root,0])
while len(d)>0:
    v,depth = d.popleft()
    ans += depth*(depth+1)//2
    ans %= mod
    for w in edge[v]:
        d.append([w,depth+1])
print(ans)