import sys
input = sys.stdin.readline

N=int(input())
E=[[] for i in range(N)]
ED=[0]*N
for i in range(N-1):
    x,y=map(int,input().split())
    E[x-1].append(y-1)
    E[y-1].append(x-1)
    ED[x-1]+=1
    ED[y-1]+=1

root=-1
for i in range(N):
    if ED[i]==1:
        if root==-1:            
            Q=[i]
            root=i

count=0
for i in range(N):
    if ED[i]>2:
        count+=1

if count>=2:
    print("No")
    exit()

L=[0]*N
while Q:
    x=Q.pop()
    for to in E[x]:
        if L[to]==0:
            L[to]=L[x]+1
            Q.append(to)

L[root]=0

flag=1
MAX=max(L)

for i in range(N):
    if ED[i]==1:
        if L[i]==MAX or i==root:
            True
        else:
            print("No")
            exit()

root=L.index(MAX)
Q=[root]

L2=[0]*N
while Q:
    x=Q.pop()
    for to in E[x]:
        if L2[to]==0:
            L2[to]=L2[x]+1
            Q.append(to)

L2[root]=0

flag=1
MAX2=max(L2)

if MAX!=MAX2:
    print("No")
    exit()

for i in range(N):
    if ED[i]==1:
        if L2[i]==MAX or i==root:
            True
        else:
            print("No")
            exit()

print("Yes")