#pragma GCC optimize("Ofast,unroll-loops,no-stack-protector,fast-math,inline")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,lzcnt,mmx,abm,avx,avx2,fma")
#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
const int N = 5e3, X = 5e6;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int n, k, c, ans;
vector<int> vt, adj[N];
bitset<N> bt[N], bt2[N], r, taken, toTake;
void clean(int x) {
for (int i = 0; i < n; i++) {
if (adj[i].size()+1 < x) r[i] = 1;
}
}
void dfs(int x) {
if (c++ > X) return;
int sz = taken.count();
if (sz > ans) {
ans = sz;
clean(sz+1);
}
shuffle(all(adj[x]), rng);
for (int& y : adj[x]) {
if (c++ > X) return;
if (r[y] || taken[y] || (taken & bt2[y]).count() < sz) continue;
taken[y] = 1;
bitset<N> toTakePrev = toTake;
toTake &= bt2[y];
dfs(y);
toTake = toTakePrev;
taken[y] = 0;
}
}
signed main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
cin >> n >> k;
ans = 1;
vt.resize(n);
for (int i = 0; i < n; i++) {
vt[i] = i;
bt2[i][i] = toTake[i] = 1;
int x; cin >> x;
for (int j = 0; j < x; j++) {
int y; cin >> y;
bt[i][y] = 1;
if (bt[y][i]) {
bt2[i][y] = 1;
adj[i].push_back(y);
bt2[y][i] = 1;
adj[y].push_back(i);
}
}
}
for (int i = 0; i < n; i++) {
if (r[i]) continue;
c = 0;
taken.reset();
taken[i] = 1;
toTake = bt2[i];
dfs(i);
}
cout << ans << "\n";
}
