#include <bits/stdc++.h>
using namespace std;
const int mx = 5e4+5;
int n, k;
bitset<mx> a[mx];
vector<int> g[mx];
int deg[mx];
set<pair<int, int>> st;
int cnt;
int c[mx];
int b[mx];
int ans = 0;
void dfs(int id, int mask, int ner) {
if (id == cnt) {
ans = max(ans, __builtin_popcount(mask));
return;
}
if ((ner & (1<<id)) and (b[id] & mask) == mask) {
dfs(id+1, mask | (1<<id), (ner & b[id]));
}
dfs(id+1, mask, ner);
}
signed main() {
cin >> n >> k;
for (int i=0;i<n;i++) {
int d;
cin >> d;
deg[i] = d;
st.insert({deg[i], i});
for (int j=0;j<d;j++) {
int x;
cin >> x;
a[i][x] = 1;
g[i].push_back(x);
}
}
while (st.size()) {
auto [it, u] = *st.begin(); st.erase(st.begin());
c[0] = u;
cnt = g[u].size()+1;
for (int i=0;i<g[u].size();i++) {
c[i+1] = g[u][i];
}
for (int i=0;i<cnt;i++) {
for (int j=0;j<cnt;j++) {
if (a[c[i]][c[j]]) {
b[i] |= 1<<j;
}
}
}
dfs(1, 1, b[0]);
}
cout << ans << "\n";
}
