#include <bits/stdc++.h>
using namespace std;
using ll = int;
using vll = vector<ll>;
using vvl = vector<vll>;
using pll = pair<ll,ll>;
using vpl = vector<pll>;
using vvp = vector<vpl>;
using vb = vector<bool>;
using vvb = vector<vb>;
#define f first
#define s second
#define pb push_back
#define all(v) v.begin(),v.end()
vll fr;
bool chek(vll q, vector<set<ll>>& g){
for(ll i = 0; i < q.size(); ++i){
for(ll j = i+1; j < q.size(); ++j){
if(!g[q[i]].count(q[j]))return 0;
}
}
return 1;
}
vvl po = {{},{},{},{7},{7,11,13,14,15}};
ll calc(vector<set<ll>>& g){
int ans = 0;
vll q;
for(ll i:po[fr.size()]){
q.clear();
for(ll j = 0; j < fr.size(); ++j){
if(i & (1<<j))q.pb(fr[j]);
}
if(chek(q,g))ans = max(ans, __builtin_popcount(i));
}
return ans;
}
ll ans = 0;
void dfs(vector<set<ll>>& g, vll& dt, ll cr){
for(ll i:g[cr]){
if(dt[i]==1e9){
dt[i]=dt[cr]+1;
dfs(g, dt, i);
}
else if(dt[i]==dt[cr]+2)ans=3;
}
}
void ch3(ll n, vector<set<ll>>& g){
vll dt(n,1e9);
for(ll i = 0; i < n; ++i){
if(dt[i]==1e9){
dt[i]=0;
dfs(g, dt, i);
}
}
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(NULL);
ll n, k, a, b;
cin >> n >> k;
if(n>0)ans=1;
vector<set<ll>> g(n);
for(ll i = 0; i < n; ++i){
cin >> a;
while(a--){
cin >> b;
g[i].insert(b);
ans=2;
}
}
ch3(n, g);
priority_queue<pll, vpl, greater<pll>> pq;
vb vs(n);
for(ll i = 0; i < n; ++i)pq.push({g[i].size(),i});
while(!pq.empty()){
auto [d, cr] = pq.top();pq.pop();
if(d!=g[cr].size())continue;
if(vs[cr])continue;
vs[cr]=1;
fr.clear();
for(ll i = 0; i < n; ++i){
if(g[cr].count(i)){
fr.pb(i);
g[i].erase(cr);
pq.push({g[i].size(), i});
}
}
ans = max(ans, 1+calc(g));
}
cout << ans;
}
