def scc(N, edges): M = len(edges) start = [0] * (N + 1) elist = [0] * M for e in edges: start[e[0] + 1] += 1 for i in range(1, N + 1): start[i] += start[i - 1] counter = start[:] for e in edges: elist[counter[e[0]]] = e[1] counter[e[0]] += 1 visited = [] low = [0] * N Ord = [-1] * N ids = [0] * N NG = [0, 0] def dfs(v): stack = [(v, -1, 0), (v, -1, 1)] while stack: v, bef, t = stack.pop() if t: if bef != -1 and Ord[v] != -1: low[bef] = min(low[bef], Ord[v]) stack.pop() continue low[v] = NG[0] Ord[v] = NG[0] NG[0] += 1 visited.append(v) for i in range(start[v], start[v + 1]): to = elist[i] if Ord[to] == -1: stack.append((to, v, 0)) stack.append((to, v, 1)) else: low[v] = min(low[v], Ord[to]) else: if low[v] == Ord[v]: while (True): u = visited.pop() Ord[u] = N ids[u] = NG[1] if u == v: break NG[1] += 1 low[bef] = min(low[bef], low[v]) for i in range(N): if Ord[i] == -1: dfs(i) for i in range(N): ids[i] = NG[1] - 1 - ids[i] group_num = NG[1] counts = [0] * group_num for x in ids: counts[x] += 1 groups = [[] for i in range(group_num)] for i in range(N): groups[ids[i]].append(i) return groups N = int(input()) edges = [] for _ in range(N): m, *A = map(int, input().split()) for a in A: edges.append((_, a - 1)) groups = scc(N, edges) M = len(groups) G = [[] for _ in range(M)] d = [0] * N for i, group in enumerate(groups): for x in group: d[x] = i for e in edges: x, y = e if d[x] != d[y]: G[d[x]].append(d[y]) if 0 not in groups[0]: print('No') else: for i in range(M - 1): if i + 1 not in G[i]: print('No') exit() print('Yes')