N = int(input())

links = [[] for _ in range(N)]
for _ in range(N - 1):
    a, b = map(lambda x: int(x) - 1, input().split())
    links[a].append(b)
    links[b].append(a)

a = sorted((len(l) for l in links), reverse=True)
if a[0] <= 2:
    print('Yes')
    exit()
elif a[1] >= 3:
    print('No')
    exit()

for i in range(N):
    if len(links[i]) < 3:
        continue
    break

root = i
d = [-1] * N
d[root] = 0
q = [root]
while q:
    i = q.pop()
    for j in links[i]:
        if d[j] != -1:
            continue
        d[j] = d[i] + 1
        q.append(j)

for i in range(root + 1, N):
    if len(links[i]) != 1:
        continue
    a = d[i]
    break

for i in range(i + 1, N):
    if len(links[i]) != 1:
        continue
    if d[i] == a:
        continue
    print('No')
    break
else:
    print('Yes')