rt

#include <bits/stdc++.h>
#define IOS ios::sync_with_stdio(0),cin.tie(0),cout.tie(0)
using namespace std;
int n,m,u,rd[505],cur,x[105],ans;
vector<int>e[505];
queue<int>q;
void js(){
	for(int i=1;i<=n;i++)if(rd[i]==0)q.push(i);
	while(!q.empty()){
		cur=q.front(),q.pop();
		for(auto i:e[cur])if(rd[i]--==1)q.push(i);
	}
}
int main(){
	IOS;
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>x[i]>>m;
		while(m--)cin>>u,e[i].push_back(u),rd[u]++;
	}
	js();
	for(int i=1;i<=n;i++)if(rd[x[i]])ans++;
	if(ans==0)cout<<"YES";
	else cout<<ans;
	return 0;
}