import sys
sys.setrecursionlimit(10**7)
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)]
def dfs(p,vis):
    ret="No"
    vis[p]+=1
    if sum(vis)==N:return "Yes"
    if len(G[p])==0:return "No"
    for n in G[p]:
        if vis[n]==0:
            ret=dfs(n,vis[:])
    for n in G[p]:
        if vis[n]<len(G[n]):
            ret=dfs(n,vis[:])
    return ret
ans=dfs(0,vis[:])
print(ans)