#include <bits/stdc++.h>
using namespace std;
const int nmax = 5e4 + 2;
set<int> adj[nmax];
bitset<nmax> f[nmax];
int ans = 0;
void calc(int i) {
for(int bit = 0; bit < (1 << adj[i].size()); bit++) {
vector<int> v;
auto pl = adj[i].begin();
for(int x = 0; (1 << x) <= bit; x++) {
if(bit & (1 << x)) {
v.push_back(*pl);
}
pl++;
}
v.push_back(i);
bool ok = 1;
for(auto it : v) {
for(auto it2 : v) {
if(it != it2 && f[it][it2] == 0) {
ok = 0;
break;
}
}
if(!ok) {
break;
}
}
if(ok) {
ans = max(ans, (int) v.size());
}
}
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n, k;
cin >> n >> k;
for(int i = 1; i <= n; i++) {
int d;
cin >> d;
while(d--) {
int j;
cin >> j;
j++;
adj[i].insert(j);
f[i][j] = 1;
}
}
set<pair<int, int>> noduri;
for(int i = 1; i <= n; i++) {
noduri.insert({adj[i].size(), i});
}
for(int _ = 1; _ <= n; _++) {
pair<int, int> top = *noduri.begin();
int i = top.second;
calc(i);
// cout << i << " ";
noduri.erase({adj[i].size(), i});
for(auto it : adj[i]) {
noduri.erase({adj[it].size(), it});
adj[it].erase(i);
noduri.insert({adj[it].size(), it});
}
}
cout << ans;
return 0;
}
