from atcoder.scc import SCCGraph

N = int(input())
M, A = [], []
scc = SCCGraph(N)
for i in range(N):
    m, *a = map(lambda x: int(x)-1, input().split())
    M.append(m)
    A.append(a)
    for j in a:
        scc.add_edge(i, j)

scc = scc.scc()

label = [-1]*N
for i, l in enumerate(scc):
    for j in l:
        label[j] = i

to = [set() for _ in range(len(scc))]
for i in range(N):
    for j in A[i]:
        if label[i] != label[j]:
            to[label[i]].add(label[j])

cnt_one = sum(len(x) == 1 for x in to)
cnt_zero = sum(len(x) == 0 for x in to)

if cnt_one == len(scc) - 1 and cnt_zero == 1:
    print("Yes")
else:
    print("No")