#include <bits/stdc++.h>
#define FAST ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);cerr.tie(0)
#define mp make_pair
#define xx first
#define yy second
#define pb push_back
#define pf push_front
#define popb pop_back
#define popf pop_front
#define all(x) x.begin(),x.end()
#define ff(i,a,b) for (int i = a; i < b; i++)
#define fff(i,a,b) for (int i = a; i <= b; i++)
#define bff(i,a,b) for (int i = b-1; i >= a; i--)
#define bfff(i,a,b) for (int i = b; i >= a; i--)
using namespace std;
long double typedef ld;
unsigned int typedef ui;
long long int typedef li;
pair<int,int> typedef pii;
pair<li,li> typedef pli;
pair<ld,ld> typedef pld;
vector<vector<int>> typedef graph;
unsigned long long int typedef ull;
//const int mod = 998244353;
const int mod = 1000000007;
//Note to self: Check for overflow
struct find_clique
{
int g[102]; //graph by bitmask
int dp1[3500]; //first half
int pc[3500]; //precalced
int dp2[3500]; //second half
void clear(int n)
{
ff(i,0,n) g[i]=0;
ff(i,0,(1<<n)) dp1[i]=0;
ff(i,0,(1<<n)) dp2[i]=0;
}
void add(int u, int v)
{
g[u]|=(1<<v);
g[v]|=(1<<u);
}
/*int calc(int n)
{
int fh=n/2,sh=(n+1)/2,fb=(1<<fh)-1,sb=(1<<sh)-1;
ff(i,0,(1<<sh)) pc[i]=__builtin_popcount(i);
ff(mask,1,(1<<fh)) ff(j,0,fh) if (mask&(1<<j)) {
dp1[mask]=max(dp1[mask],dp1[mask&g[j]]+1);
}
ff(mask,1,(1<<sh)) ff(j,0,sh) if (mask&(1<<j)) {
dp2[mask]=max(dp2[mask],dp2[mask&(g[j]>>fh)]+1);
}
int ans=0;
ff(mask,0,(1<<sh)) if (dp2[mask]==pc[mask])
{
int span=0;
ff(j,0,sh) if (mask&(1<<j)) span|=(g[j]&fb);
ans=max(ans,pc[mask]+dp1[span]);
}
return ans;
}*/
int calc(int n)
{
int ans=0;
ff(mask,0,(1<<n))
{
bool dobar=true;
ff(j,0,n) if (mask&(1<<j)) if (((g[j]|(1<<j))&mask)!=mask) dobar=false;
if (dobar) ans=max(ans,__builtin_popcount(mask));
}
return ans;
}
} ok;
set<pii> pq;
set<int> idemo[100005];
int main()
{
FAST;
int n,k; cin>>n>>k;
ff(i,0,n)
{
int d; cin>>d;
while (d--)
{
int x; cin>>x;
idemo[i].insert(x);
}
}
ff(i,0,n) pq.insert({(int)idemo[i].size(),i});
int ans=1;
while (!pq.empty())
{
int p=pq.begin()->yy;
vector<int> cvors;
cvors.pb(p);
for (auto it : idemo[p]) cvors.pb(it);
/*cout<<"consider: ";
for (auto it : cvors) cout<<it<<" "; cout<<endl;*/
ok.clear((int)cvors.size());
ff(i,0,(int)cvors.size())
ff(j,i+1,(int)cvors.size())
if (idemo[cvors[i]].count(cvors[j]))
ok.add(i,j);
ans=max(ans,ok.calc((int)cvors.size()));
for (auto it : idemo[p]) pq.erase({(int)idemo[it].size(),it}),idemo[it].erase(p),pq.insert({(int)idemo[it].size(),it});
pq.erase({(int)idemo[p].size(),p});
}
cout<<ans<<"\n";
}
//Note to self: Check for overflow
/*
5 3
2 1 2
3 0 2 3
3 0 1 4
2 1 4
2 2 3
*/
