#嘘解法で通します。ごめんなさい…

from collections import deque

N = int(input())
L = []
for i in range(N):
    L.append([])
for i in range(N-1):
    a,b = map(int, input().split())
    L[a-1].append(b-1)
    L[b-1].append(a-1)
CHECK = []
overT = False
for i in range(N):
    if len(L[i])==1:
        CHECK.append(i)
    if overT and len(L[i])>=3:
        print('No')
        exit()
    if len(L[i])>=3:
        overT = True


root = CHECK[0]

q = deque()
c = deque()

STEP = [-1]*N
STEP[root]=0
q.append(root)
c.append(0)


while len(q) !=0:
    i = q.popleft()
    cnt = c.popleft()
    for l in L[i]:
        if STEP[l]==-1:
            STEP[l]=cnt+1
            q.append(l)
            c.append(cnt+1)



ans = True
for i in range(len(CHECK)):
    ans = ans and (STEP[CHECK[i]]==0 or STEP[CHECK[i]]==STEP[CHECK[1]]) 
same = STEP[CHECK[1]]

root = CHECK[-1]
STEP = [-1]*N
STEP[root]=0
q.append(root)
c.append(0)

while len(q) !=0:
    i = q.popleft()
    cnt = c.popleft()
    for l in L[i]:
        if STEP[l]==-1:
            STEP[l]=cnt+1
            q.append(l)
            c.append(cnt+1)

for i in range(len(CHECK)):
    ans = ans and (STEP[CHECK[i]]==0 or STEP[CHECK[i]]==same) 

if ans:
    print('Yes')
else:
    print('No')