from collections import defaultdict
N = int(input())
edge = defaultdict(list)
for i in range(1,N+1):
    A = list(map(int, input().split()))[1:]
    edge[i] = A
  

def dfs(start):
    todo = [start,]
    seen = [False] * (N+1)

    while todo:
        tgt = todo.pop()
        if seen[tgt]:
            continue
        seen[tgt] = True

        for next in edge[tgt]:
            todo.append(next)
    
    return seen

connected = dfs(1)
if(all(connected[1:])):
    print("Yes")
else:
    print("No")