#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#include <iostream>
#include <string.h>
#include <string>
#include <vector>
#include <algorithm>
#include <map>
#include <cmath>
#include <memory.h>
#include <set>
using namespace std;
#define rep(i, n) for(int i =0;i<(n);i++)
#define per(i, n) for (int i=((int)n-1);i>=0;i--)
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define ff first
#define ss second
#define make_unique(x) { sort(all(x)); x.resize(unique(x.begin(), x.end()) - x.begin()); }
#define sz(x) ((int)x.size())
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define add insert
#define debug(x) { cerr << #x << "= " << x << "\n"; }
typedef long long ll;
typedef vector<int>vi;
typedef vector<ll> vll;
typedef pair<int, int> pii;
typedef vector<pii> vpii;
typedef pair<ll, ll> pll;
const int N = 50000;
set<int> g[N];
int max_click(vi v) {
int res = 0;
for (int mask = 1; mask < (1 << sz(v)); mask++) {
vi u;
rep(i, sz(v)) {
if (mask & (1 << i)) {
u.pb(v[i]);
}
}
bool ok = true;
rep(i, sz(u)) {
for (int j = i + 1; j < sz(u); j++) {
if (g[u[i]].count(u[j]) == 0) {
ok = false;
}
}
}
if (ok) {
res = max(res, sz(u));
}
}
return res;
}
int main() {
int n, k;
cin >> n >> k;
rep(i, n) {
int d;
cin >> d;
rep(j, d) {
int x;
cin >> x;
g[i].add(x);
}
}
set<pii> bdeg;
rep(i, n) {
bdeg.add({ sz(g[i]), i });
}
int ans = 0;
while (sz(bdeg)) {
int v = bdeg.begin()->ss;
bdeg.erase(bdeg.begin());
vi cand;
for (int u : g[v]) {
cand.pb(u);
}
cand.pb(v);
ans = max(ans, max_click(cand));
for (int u : g[v]) {
bdeg.erase(mp(sz(g[u]), u));
g[u].erase(v);
bdeg.add(mp(sz(g[u]), u));
}
}
cout << ans;
return 0;
}
