#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i, n) for(int i=0;i<(n);++i)
#define rep1(i, n) for(int i=1;i<=(n);i++)
#define ll long long
using mint = modint998244353;
using P = pair<ll,ll>;
using lb = long double;
using T = tuple<ll, ll, ll>;
#ifdef LOCAL
#  include <debug_print.hpp>
#  define dbg(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define dbg(...) (static_cast<void>(0))
#endif

int main()
{
    int n;
    cin >> n;
    vector<vector<int>> g(n);
    dsu uf(n);
    vector<int> d(n);
    rep(i,n) {
        int m;
        cin >> m;
        d[i] = m;
        rep(j,m) {
            int b;
            cin >> b;
            --b;
            uf.merge(i,b);
            g[b].push_back(i);
        }
    }
    if(uf.groups().size()!=1){
        cout<<"No"<<endl;
        return 0;
    }
    queue<int> q;
    rep(i,n) {
        if(d[i]==0) q.push(i);
    }
    while(!q.empty()) {
        if(q.size()>2) {
            cout << "No" << endl;
            return 0;
        }
        int u = q.front();q.pop();
        for(int v : g[u]) {
            d[v]--;
            if(d[v]==0) q.push(v);
        }
    }
    cout << "Yes" << endl;
    return 0;
}