#include<bits/stdc++.h> //:3
using namespace std;
typedef long long ll;
#define all(a) (a).begin(), (a).end()
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define pi pair<long double, long double>
#define sz(x) (int)((x).size())
//#define int long long
const int dx[] = {0, 1, 0, -1};
const int dy[] = {1, 0, -1, 0};
const ll inf = 2e9;
const ll mod = 1e9 + 7;
const int N = 2e4 + 11;
const ll INF64 = 2e9;
const double eps = 1e-14;
const double PI = acos(-1);
//ifstream in(".in");
//ofstream out(".out");
int n, viz[N], d[N];
vector<int>v[N];
int bfs(int x){
for(int i = 1; i <= n; i++)viz[i] = 0, d[i] = 0;
d[x] = 1;
viz[x] = 1;
queue<int>q;
q.push(x);
while(!q.empty()){
int nod = q.front();
q.pop();
for(auto it : v[nod]){
if(viz[it])continue;
viz[it] = 1;
d[it] = d[nod] + 1;
q.push(it);
}
}
int ans = 0;
for(int i = 1; i <= n; i++){
if(!viz[i])return -1;
ans += d[i];
}
return ans;
}
void solve(){
cin >> n;
for(int i = 1, k; i <= n; i++){
cin >> k;
for(int j = 1, x; j <= k; j++){
cin >> x;
v[x].push_back(i);
}
}
int ans = INF64;
for(int i = 1; i <= n; i++){
int x = bfs(i);
if(x != -1)ans = min(ans, x);
}
if(ans == INF64){
cout << "-1" << '\n';
return;
}
cout << ans << '\n';
}
int32_t main(){
ios_base :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
//cout << setprecision(6) << fixed;
int T = 1;
//cin >> T;
while(T--){
solve();
}
}
