#include <bits/stdc++.h>
using namespace std;
#define F0R(i, n) for (int i= 0 ; i< n;i++)
#define FOR(i,j,n) for (int i = j; i< n;i++)
template<typename T>
using V = vector<T>;
using vi = V<int>;
using pi = pair<int,int>;
int solve(V<set<int>> g) {
int ans = 0;
F0R(i, 1 << g.size()) {
bitset<20> b = i;
bool pos = true;
F0R(j, g.size()) {
F0R(k, g.size()) {
if (b[j] and b[k] and !g[j].contains(k) and j != k) {
pos = false;
break;
}
}
if (!pos) break;
}
if (pos)
ans = max(ans,(int) b.count());
}
return ans;
}
int main() {
int n, k; cin >> n >> k;
V<set<int>> g(n);
set<pi> pq;
F0R(i, n) {
int d; cin >> d;
F0R(j, d) {
int y; cin >> y;
g[i].insert(y);
}
}
F0R(i, n) {
for (auto y : g[i]) {
if (!g[y].count(i)) exit(5);
}
}
F0R(i, n) {
pq.insert({g[i].size(), i});
}
int ans = 0;
while (!pq.empty()) {
auto [am, node] = *pq.begin(); pq.erase(pq.begin());
V<set<int>> miniG(g[node].size() + 1);
map<int, int> decompose;
decompose[node] = 0;
int nextId = 1;
for (auto y : g[node])
decompose[y] = nextId++;
// todo optimize this loop
for (auto y : g[node]) {
for (auto z : g[y]) {
if (!decompose.count(z)) continue;
miniG[decompose[y]].insert(decompose[z]);
}
miniG[0].insert(decompose[y]);
}
ans = max(ans, solve(miniG));
for (auto y : g[node]) {
pq.erase({g[y].size(), y});
g[y].erase(node);
}
for (auto y : g[node]) {
pq.insert({g[y].size(), y});
}
g[node].clear();
}
cout << ans;
}
