from collections import deque

N = int(input())
G = [[] for _ in range(N)]
zero = 0
for i in range(N):
    MA = list(map(int, input().split()))
    M = MA[0]
    if M == 0:
        zero += 1
    A = MA[1:]
    for j in range(M):
        G[i].append(A[j]-1)

visited = [False]*N
visited[0] = True
que = deque()
que.append(0)
while que:
    n = que.popleft()
    for v in G[n]:
        if not visited[v]:
            visited[v] = True
            que.append(v)

if sum(visited) < N or zero >= 2:
    print("No")
else:
    print("Yes")