#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
using namespace std;
#define int long long
#define pb push_back
#define nl '\n'
#define fore(i, y) for(int i = 0; i < y; i++)
#define forr(i, x, y) for(int i = x;i<=y;i++)
#define forn(i, y, x) for(int i = y; i >= x; i--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int N = 50000;
vector<bitset<N>> adj(N , 0);
int n , k;
bitset<N> cur = 0;
//bool done[N];
int maxClique(int i)
{
cur = adj[i];
int last = i;
int cnt = 0;
while(true)
{
cnt++;
cur&=adj[last];
vector<int> candidates;
for(int j = cur._Find_first() ; j < N ; j = cur._Find_next(j))
{
candidates.pb(j);
}
if(candidates.empty())
break;
last = candidates[uniform_int_distribution<int>(0 , (int)candidates.size() - 1)(rng)];
}
return cnt;
}
signed main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin>>n>>k;
fore(i , n)
{
int d;
cin>>d;
fore(j , d)
{
int x;
cin>>x;
if(x != i)
adj[i][x] = 1;
}
}
int best = 0;
vector<int> p(n);
fore(i , n)
p[i] = i;
fore(i , 10 * n)
{
if(i % n == 0)
{
shuffle(p.begin() , p.end() , rng);
}
best = max(best , maxClique(p[i%n]));
}
cout<<best<<nl;
}
