n=int(input())
d=[]
for i in range(n):
  m,*a=map(int,input().split())
  d+=[i-1 for i in a],
q=[0]
s=[0]*n
s[0]=1
while q:
  p=q.pop()
  for v in d[p]:
    if s[v]<1:
      s[v]=1
      q+=v,
if sum(s)==n:
  print('Yes')
else:
  print('No')