from collections import defaultdict,deque

def main():
    N = int(input())
    d = defaultdict(list)

    for i in range(N):
        que = list(map(int, input().split()))
        d[i+1] = que[1:]
    
    que = deque([1])
    s = set([1])

    while que:
        v = que.popleft()
        for u in d[v]:
            if u not in s:
                s.add(u)
                que.append(u)
    
    if len(s) == N:
        print("Yes")
    else:
        print("No")
        

if __name__ == "__main__":
    main()