n=int(input())
l=[list(map(int,input().split())) for i in range(n-1)]
connection=[[] for i in range(n)]
for i in range(n-1):
  connection[l[i][0]-1].append(l[i][1]-1)
  connection[l[i][1]-1].append(l[i][0]-1)

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

def bfs(v):
  distance=[-1]*n
  distance[v]=0
  next=connection[v]
  next2=set()
  visited=[-1]*n
  visited[v]=1
  visitct=1
  ct=0
  while len(next)!=0 and visitct!=n:
    ct+=1
    for i in range(len(next)):
      if visited[next[i]]==-1:
        distance[next[i]]=ct
        visited[next[i]]=1
        visitct+=1
        for j in range(len(connection[next[i]])):
          if visited[connection[next[i]][j]]==-1:
            next2.add(connection[next[i]][j])
    next=list(next2)
    next2=set()
  return distance

for i in range(min(10,len(L))):
  B=bfs(L[i])
  ans=[]
  for j in range(len(L)):
    if j!=i:
      x=L[j]
      ans.append(B[x])
  if len(set(ans))!=1:
    print('No')
    exit()
print('Yes')