from collections import deque

n = int(input())
e = [[] for i in range(n)]
for i in range(n-1):
    a,b = map(int,input().split())
    a -= 1
    b -= 1
    e[a].append(b)
    e[b].append(a)

cand = []
for i in range(n):
    if len(e[i]) == 1:
        cand.append(i)

def search(ind):
    dis = [10**10]*n
    dis[cand[ind]] = 0

    q = deque([cand[ind]])
    while q:
        now = q.popleft()
        for nex in e[now]:
            if dis[nex] > dis[now]+1:
                dis[nex] = dis[now]+1
                q.append(nex)
    num = dis[cand[(ind+1)%len(cand)]]
    for i in cand:
        if i != cand[ind] and num != dis[i]:
            print("No")
            exit()
search(0)
search(1)
print("Yes")