import sys
sys.setrecursionlimit(10**6)
N = int(input())
FG = {i:[] for i in range(1,N+1)}
for i in range(1,N+1):
    A = list(map(int,input().split()))
    for j in range(1,A[0]+1):
        FG[i].append(A[j])
A = [0]*(N+1)
invA = [0]*(N+1)
visited = [0]*(N+1)
cnt = 1
def dfs1(v):
    global cnt
    visited[v] = 1
    for u in FG[v]:
        if visited[u]==0:
            dfs1(u)
    A[v] = cnt
    invA[cnt] = v
    cnt += 1
for i in range(1,N+1):
    if visited[i]==0:
        dfs1(i)
BG = {i:[] for i in range(1,N+1)}
for i in range(1,N+1):
    for j in FG[i]:
        BG[j].append(i)         
Col = [0]*(N+1)
cnt = 1
def dfs2(v,cnt):
    Col[v] = cnt
    for u in BG[v]:
        if Col[u]==0:
            dfs2(u,cnt)
for i in range(N,0,-1):
    if Col[invA[i]]==0:
        dfs2(invA[i],cnt)
        cnt += 1
G = {c:set([]) for c in range(1,cnt)}
for i in range(1,N+1):
    c = Col[i]
    for j in FG[i]:
        if Col[j]!=c:
            G[c].add(Col[j])
if cnt-1==1:
    print("Yes")
else:
    inDeg = [0]*cnt
    outDeg = [0]*cnt
    for c in G:
        outDeg[c] = len(G[c])
        for d in G[c]:
            inDeg[d] += 1
    edge = sum(outDeg)
    if edge==cnt-2 and inDeg[1:].count(0)==1 and outDeg[1:].count(0)==1:
        print("Yes")
    else:
        print("No")