#include <bits/stdc++.h>
using namespace std;
#define isz(a) (int)(a).size()
const int NM = 5e4, KM = 10, BL = 320;
int N, K;
vector <int> adj[NM+5];
vector <vector <int> > clique[KM+5];
vector <int> common(vector <int> &a, vector <int> &b){
vector <int> c = {};
if (isz(a) > isz(b)){
for (int i = 0; i < isz(b); i++){
if (b[i] > a.back()) break;
int j = lower_bound(a.begin(), a.end(), b[i])-a.begin();
if (b[i] == a[j]) c.push_back(b[i]);
}
}
else{
for (int i = 0; i < isz(a); i++){
if (a[i] > b.back()) break;
int j = lower_bound(b.begin(), b.end(), a[i])-b.begin();
if (a[i] == b[j]) c.push_back(a[i]);
}
}
return c;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> N >> K;
for (int i = 0; i < N; i++){
int k; cin >> k;
adj[i].resize(k);
for (int &j : adj[i]) cin >> j;
sort(adj[i].begin(), adj[i].end());
}
for (int i = 0; i < N; i++) clique[1].push_back({i});
for (int i = 1; i < K; i++){
vector <int> vlist, arr_next;
for (vector <int> arr : clique[i]){
int mn = 0;
for (int j = 1; j < i; j++)
if (isz(adj[arr[j]]) < isz(adj[arr[mn]])) mn = j;
vlist = adj[arr[mn]];
for (int j = 0; j < i; j++)
if (j != mn) vlist = common(vlist, adj[arr[j]]);
for (int x : vlist){
if (x <= arr.back()) continue;
arr_next = arr;
arr_next.push_back(x);
clique[i+1].push_back(arr_next);
}
}
}
int res = K;
while (isz(clique[res]) == 0) res--;
cout << res;
return 0;
}
