913B - Christmas Spruce

119557653

CODE:-

n= int(input()) ls=[] for i in range(n): ls.append([])

for i in range(2,n+1): j=int(input()) ls[j-1].append(i)

for i in ls: for j in i: if ls[j-1]: i.remove(j)

ls = list(filter(([]).__ne__, ls))

if len(min(ls))<3: print('No') else: print('Yes')