n=int(input())
uf=[*range(n)]
def find(x):
 q=[]
 while uf[x]^x:q+=x,;x=uf[x]
 for p in q:uf[p]=x
 return x
def unite(x,y):
 x,y=find(x),find(y)
 if x^y:uf[x]=y
for i in range(n):
  m,*a=map(int,input().split())
  for j in a:
    unite(i,j-1)
s=set()
for i in range(n):
  s|={find(i)}
if len(s)==1:
  print('Yes')
else:
  print('No')