#include <bits/stdc++.h>
using namespace std;
const int nx=5e4+5;
int n, k, x, y, res;
set<int> d[nx];
set<pair<int, int>> s;
int main()
{
cin.tie(NULL)->sync_with_stdio(false);
cin>>n>>k;
for (int i=0; i<n; i++)
{
cin>>x;
for (int j=1; j<=x; j++) cin>>y, d[i].insert(y);
s.insert({d[i].size(), i});
}
while (!s.empty())
{
auto [sz, x]=*s.begin();
//cout<<"debug "<<s.size()<<' '<<sz<<' '<<x<<'\n';
s.erase(s.begin());
vector<int> v;
//cout<<"node ";
for (auto tmp:d[x]) v.push_back(tmp);//cout<<tmp<<' ';
//cout<<'\n';
for (int msk=0; msk<(1<<sz); msk++)
{
vector<int> t;
for (int i=0; i<sz; i++) if (msk&(1<<i)) t.push_back(v[i]);
int cnt=__builtin_popcount(msk);
bool can=1;
for (int i=0; i<cnt; i++) for (int j=i+1; j<cnt; j++) if (d[t[i]].find(t[j])==d[t[i]].end()) can=0;
if (can) res=max(res, cnt+1);
}
for (auto tmp:d[x]) s.erase(make_pair(d[tmp].size(), tmp)), d[tmp].erase(x), s.insert({d[tmp].size(), tmp});
}
cout<<res;
}
