import collections
N, = map(int, input().split())
graph = collections.defaultdict(list)
for i in range(1, N + 1):
    Mi, *neigb = map(int, input().split())
    for neighbor in neigb:
        graph[i].append(neighbor)
visited = set()
queue = collections.deque([1])
while queue:
    node = queue.popleft()
    if node not in visited:
        visited.add(node)
        for neighbor in graph[node]:
            if neighbor not in visited:
                queue.append(neighbor)
if len(visited) == N:
    print("Yes")
else:
    print("No")