class UnionFind:
    def __init__(self, n):
        self.n = n
        self.parent_size = [-1] * n
    def leader(self, a):
        if self.parent_size[a] < 0: return a
        self.parent_size[a] = self.leader(self.parent_size[a])
        return self.parent_size[a]
    def merge(self, a, b):
        x, y = self.leader(a), self.leader(b)
        if x == y: return
        if abs(self.parent_size[x]) < abs(self.parent_size[y]): x, y = y, x
        self.parent_size[x] += self.parent_size[y]
        self.parent_size[y] = x
        return
    def same(self, a, b):
        return self.leader(a) == self.leader(b)
    def size(self, a):
        return abs(self.parent_size[self.leader(a)])
    def groups(self):
        result=[[] for _ in range(self.n)]
        for i in range(self.n):
            result[self.leader(i)].append(i)
        return [r for r in result if r != []]
N=int(input())
UF=UnionFind(N)
for i in range(N):
    T=list(map(int,input().split()))
    F=list(map(lambda x:x-1,T[1:]))
    for f in F:
        UF.merge(i,f)
if len(UF.groups())==1:print("Yes")
else:print("No")