n = int(input())
m = [[] for _ in [0]*n] # 近傍
for _ in [0]*(n-1):
    a, b = map(int, input().split())
    m[a-1] += [b-1]
    m[b-1] += [a-1]
print('YNeos'[not(sum(len(i)>2for i in m)==1 and sum(len(i)==2for i in m)==0 or all(len(i)<3for i in m))::2])