#include <bits/stdc++.h>
using namespace std;
using ll = long long;
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(ll wh, vvb& mat){
for(ll i = 0; i < fr.size(); ++i){
if(!(wh & (1<<i)))continue;
for(ll j = i+1; j < fr.size(); ++j){
if(!(wh & (1<<j)))continue;
if(!mat[fr[i]][fr[j]])return 0;
}
}
return 1;
}
ll calc(vvb& mat){
int ans = 0;
for(ll i = 0; i < (1<<fr.size()); ++i){
if(chek(i,mat))ans = max(ans, __builtin_popcount(i));
}
return ans;
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(NULL);
ll n, k, a, b;
cin >> n >> k;
vector<set<ll>> g(n);
vvb mat(n, vb(n));
vll dg(n);
for(ll i = 0; i < n; ++i){
cin >> a;
dg[i]=a;
while(a--){
cin >> b;
g[i].insert(b);
mat[i][b]=1;
}
}
priority_queue<pll, vpl, greater<pll>> pq;
vb vs(n);
ll ans = 0;
for(ll i = 0; i < n; ++i)pq.push({dg[i],i});
while(!pq.empty()){
auto [d, cr] = pq.top();pq.pop();
if(d!=dg[cr])continue;
if(vs[cr])continue;
vs[cr]=1;
fr.clear();
for(ll i = 0; i < n; ++i){
if(mat[cr][i]){
fr.pb(i);
mat[i][cr]=0;
mat[cr][i]=0;
dg[i]--;
pq.push({dg[i], i});
}
}
ans = max(ans, 1+calc(mat));
}
cout << ans;
}
