mod = 1000000007
eps = 10**-9


def main():
    import sys
    from collections import deque
    input = sys.stdin.buffer.readline

    def f(n):
        return (n * (n+1) // 2)%mod

    N = int(input())
    par = [0] * (N+1)
    child = [[] for _ in range(N+1)]
    for _ in range(N-1):
        a, b = map(int, input().split())
        par[b] = a
        child[a].append(b)

    for v in range(1, N+1):
        if par[v] == 0:
            v0 = v
            break
    depth = [-1] * (N+1)
    que = deque()
    que.append(v0)
    ans = 0
    while que:
        v = que.popleft()
        depth[v] = depth[par[v]] + 1
        for u in child[v]:
            que.append(u)
        ans = (ans + f(depth[v]))%mod
    print(ans)


if __name__ == '__main__':
    main()