#include "bits/stdc++.h"
using namespace std;
struct node{
	int w;
	int to[2200];
	int tonum;
	int din;
} cam[2200];
int n, m, x, to, ans;
bool flag;
//vector <int> g[110]; 
void dfs(){
	for (int i = 1; i <= n; i++){
		if (cam[i].din == 0 && cam[i].w != 0){
			cam[i].w = 0;
			for (int j = 1; j <= cam[i].tonum; j++) cam[cam[i].to[j]].din--;
			dfs();
		}
	}
}
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin >> n;
	for (int i = 1; i <= n; i++){
		cin >> x >> m;
		cam[x].tonum = m;
		cam[x].w = x;
		for (int j = 1; j <= m; j++){	
			cin >> to;
			cam[x].to[j] = to;
			cam[cam[x].to[j]].din++;
		}
	}
	for (int i = 1; i <= n; i++)
		cout << "cam[i].din=" << cam[i].din << endl;
	dfs();
	for (int i = 1; i <= n; i++){
		cout << "cam[i].din=" << cam[i].din << endl;
		if (cam[i].w != 0) ans++;
	}
		
	if (ans != 0) cout << ans;
	else cout << "YES";
	return 0;
}
/*
6
98 1 151
100 2 98 120
120 0
151 1 160
160 2 98 100
500 1 120
*/