# 1-idx
# LCAっぽい気がしている。
# 長さから含まれるpathの総和は求められる
# 包除原理っぽくやる。
import sys

input = sys.stdin.buffer.readline

mod = 10 ** 9 + 7
n = int(input())
graph = [[] for _ in range(n + 1)]
in_num = [0] * (n + 1)
par = [-1] * (n + 1)
for _ in range(n - 1):
    a, b = map(int, input().split())
    par[b] = a
    graph[a].append(b)

root = -1
# 根がどれか確認
for i in range(1, n + 1):
    if par[i] == -1:
        root = i
assert root > 0

# 考慮すべき葉のリストを作る
mattan = []


# 長さi経路に含まれるpathの和
def path_calc(length):
    return (length * (length + 1) * (length + 2) // 6) % mod


# LCAの準備のeuler&first&depth heavyはいらんな。
def dfs(start):
    idx = 0
    euler = []
    depth = [-1] * (n + 1)
    depth[start] = 0
    stack = []
    first = [-1] * (n + 1)
    stack.append(~start)
    stack.append(start)
    while stack:
        v = stack.pop()
        if v > 0:
            d = depth[v]
            euler.append(v)
            first[v] = idx
            idx += 1
            # 子供がないところは末端。
            if not graph[v]:
                mattan.append(v)
            for u in graph[v]:
                depth[u] = d + 1
                stack.append(~u)
                stack.append(u)
        else:
            a = ~v
            euler.append(par[a])
            idx += 1
    return depth, euler, first


depth, euler, first = dfs(root)

# segment tree
nagasa = len(euler)
num = 2 ** (nagasa.bit_length())
infi = 10 ** 10
SEG = [infi] * (2 * num)


def func(a, b):
    return min(a, b)


def update(idx, val):
    idx += num
    SEG[idx] = val
    while idx > 0:
        idx //= 2
        SEG[idx] = func(SEG[2 * idx], SEG[2 * idx + 1])


def query(a, b):  # 閉区間。
    res = infi
    a += num
    b += num
    while b - a > 0:
        if (a & 1) == 1:
            res = func(res, SEG[a])
            a += 1
        if (b & 1) == 0:
            res = func(res, SEG[b])
            b -= 1
        a //= 2
        b //= 2
    if a == b:
        res = func(SEG[a], res)
    return res


for idx, val in enumerate(euler):
    update(idx, depth[val])

nagasa = len(mattan)
if nagasa == 1:
    ans = path_calc(depth[mattan[-1]]) % mod
else:
    ans = path_calc(depth[mattan[0]]) % mod
    for i in range(1, nagasa):
        # print(ans)
        now = mattan[i]
        NOW = first[now]
        pre = mattan[i - 1]
        PRE = first[pre]
        ans += path_calc(depth[now])
        ans %= mod
        if NOW < PRE:
            NOW, PRE = PRE, NOW
        sosen = query(PRE, NOW)
        ans -= path_calc(sosen)
        ans %= mod
print(ans)