#include <bits/stdc++.h>
//#define int int64_t
using namespace std;
constexpr int MAXN = 50009;
set <int> g[MAXN];
vector <int> d;
int ans = 1;
int n, k;
mt19937 rng( chrono::steady_clock::now().time_since_epoch().count() );
void dfs(int v, set <int> vv) {
if(d[v] < (int)vv.size()) return;
for(auto j : vv) {
if( !g[ v ].count( j ) ) {return;}
}
vv.insert(v);
if((int)vv.size() == k) {
cout << k;
exit(0);
}
ans = max(ans, (int)vv.size() );
for(auto to : g[v]) {
if( !vv.count( to ) ) {
dfs(to, vv);
}
}
}
void solve() {
cin >> n >> k;
d.resize(n + 1);
bool sub3 = 1;
vector <pair <int,int>> vvv;
for(int i = 1; i <= n; i++ ){
cin >> d[i];
vvv.emplace_back( d[i], i );
if(d[i] > 10) {
sub3 = 0;
}
for(int j = 0; j < d[i]; j++) {
int x;
cin >> x;
x++;
g[ i ].insert(x);
}
}
if(sub3 == 1 || (k <= 3 && n <= 5000)) {
for(int i = 1; i <= n; i++) {
dfs(i, {});
}
cout << ans;
return;
}
else{
for(int i = 1; i <= min(300, n); i++) {
dfs(i, {});
}
for(int i = n; i >= max(1, n - 300); i--) {
dfs(i, {});
}
sort(vvv.begin(), vvv.end());
reverse(vvv.begin(), vvv.end());
for(int j = 0; j < min(301, (int)vvv.size()); j++ ){
int i = vvv[j].second;
dfs(i, {});
}
for(int j = 0; j < 300; j++) {
int i = rng() % n + 1;
dfs(i, {});
}
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();
}
}
