n=int(input())
mod=10**9+7
es=[[] for _ in range(n)]
par=[-1]*n
for _ in range(n-1):
    a,b=map(int,input().split())
    es[a-1].append(b-1)
    if par[b-1]==-1:
        par[b-1]=a-1

for i in range(n):
    if par[i]==-1:
        root=i
        break
stack=[(root,0)]
ans=0

from collections import defaultdict
d=defaultdict(int)

while stack:
    now,depth=stack.pop()
    d[depth]+=1
    for e in es[now]:
        stack.append((e, depth+1))

for k in d.keys():
    ans+=d[k]*k*(k+1)//2
    ans%=mod

print(ans)