#include <bits/stdc++.h>
#define int int64_t
using namespace std;
constexpr int MAXN = 50009, inf = 1e18;
set <int> g[MAXN];
vector <int> cand[MAXN];
void solve() {
int n, k;
cin >> n >> k;
set <pair <int, int>> s;
for(int i = 1; i <= n; i++) {
int d;
cin >> d;
for(int j = 0; j < d; j++) {
int x;
cin >> x;
x++;
g[i].insert(x);
}
s.insert({ d, i });
}
vector <bool> used(n + 1, 1);
int ans = 1;
for(auto [_, v] : s) {
used[v] = 0;
cand[ v ].emplace_back(v);
for(auto to : g[v]) {
if( used[to] ) {
cand[ v ].emplace_back(to);
}
}
}
vector <int> vv;
for(int v = 1; v <= n; v++) {
swap(vv, cand[v]);
int sz = (int)vv.size();
int mx = 1;
vector <int> daun;
for(int bt = 0; bt < (1 << sz); bt++) {
if(!used[bt] ) continue;
daun.clear();
int cnt = 0;
for(int i = 0; i < sz; i++) {
if( ((bt >> i) & 1) ) {
cnt++;
daun.emplace_back(vv[i]);
}
}
bool ok = 1;
for(int i = 0; i < cnt; i++) {
int u = daun[i];
for(int j = i + 1; j < cnt; j++) {
int v = daun[j];
if(!g[u].count(v) || !g[v].count(u)) {
ok = 0;
break;
}
}
if(!ok) break;
}
if(ok){
mx = max(mx, cnt);
}
}
ans = max(ans, mx);
}
cout << ans;
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//freopen("7-router.in", "r", stdin);
//freopen("7-router.out.txt", "w", stdout);
int tt = 1;
//cin >> tt;
while (tt--){
solve();
}
}
