N = int(input())
G = [[] for _ in range(N)]
for _ in range(N):
	m,*A = list(map(int,input().split()))
	
	for a in A:
		G[_].append(a - 1)
		
ans = 1
memo = [0] * N
stack = [0]
memo[0] = 1
while stack:
	now = stack.pop()
	for a in G[now]:
		if memo[a] == 0:
			ans += 1
			memo[a] = 1
			stack.append(a)
print('Yes' if ans == N else "No")