#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int mxN = 5e3+10;
vector<int> edges[mxN];
int N;
int bfs(int st) {
queue<pair<int, int>> q;
vector<int> VIS(N+1, 0);
q.push({1, st});
int ret = 0;
while(q.size()) {
auto node = q.front();
q.pop();
if (VIS[node.second])
continue;
VIS[node.second] = 1;
ret += node.first;
for (auto c : edges[node.second]) {
if (!VIS[c])
q.push({node.first+1, c});
}
}
for (int i = 1; i <= N; i++) {
if (!VIS[i]) {
ret = INT_MAX;
break;
}
}
return ret;
}
void solve() {
cin >> N;
for (int i = 1; i <= N; i++) {
int K;
cin >> K;
for (int j = 0; j < K; j++) {
int boss;
cin >> boss;
edges[boss].push_back(i);
}
}
int ans = INT_MAX;
for (int i = 1; i <= N; i++)
ans = min(ans, bfs(i));
if (ans == INT_MAX)
ans = -1;
cout << ans;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
solve();
}
