#include <bits/stdc++.h>
using namespace std;
template<typename T>
void out(T x) { cout << x << endl; exit(0); }
#define watch(x) cout << (#x) << " is " << (x) << endl
using ll = long long;
const int maxn = 5e4 + 10;
int n,k;
set<int> g[maxn];
int main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin>>n>>k;
for (int i=0; i<n; i++) {
int t;
cin>>t;
while (t--) {
int x;
cin>>x;
g[i].insert(x);
g[x].insert(i);
}
}
queue<int> qq;
vector<bool> added(n, false);
for (int i=0; i<n; i++) {
if ((int)g[i].size()<k) {
qq.push(i);
added[i] = true;
}
}
int ans = 0;
while (qq.size()) {
int at = qq.front();
qq.pop();
int len = g[at].size();
for (int mask=0; mask<(1<<len); mask++) {
int val = __builtin_popcount(mask);
if (val <= ans) {
continue;
}
int tmp = mask;
vector<int> w;
for (int x: g[at]) {
if (tmp&1) {
w.push_back(x);
}
tmp >>= 1;
}
int N = w.size();
bool ok = true;
for (int i=0; i<N && ok; i++) {
for (int j=i+1; j<N && ok; j++) {
ok &= (g[w[i]].count(w[j]));
}
}
if (ok) {
ans = max(ans, val);
}
}
for (int to: g[at]) {
g[to].erase(at);
if ((int)g[to].size()<k && !added[to]) {
qq.push(to);
}
}
g[at].clear();
}
cout<<ans+1<<endl;
return 0;
}
