from collections import deque
N=int(input())
G=[[] for _ in range(N)]
for i in range(N):
    T=list(map(int,input().split()))
    G[i].extend(list(map(lambda x:x-1, T[1:])))
vis=[0 for _ in range(N)]
Q=deque([0])
while Q:
    p=Q.popleft()
    vis[p]=1
    for n in G[p]:
        if vis[n]==0:Q.append(n)
if sum(vis)==N:print("Yes")
else:print("No")