#include <bits/stdc++.h>
using namespace std;
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("Ofast,unroll-loops,fast-math,O3")
#define pb push_back
#define ll long long
#define f first
#define s second
#define sz(v) int(v.size())
#define all(v) v.begin(),v.end()
int mod = 1e9 + 7;
const int N = 1048576 + 100;
const ll inf = 2e18;
vector <int> g[N],gr[N],cmp(N);
vector <int> top;
int cur;
int was[N],cnt[N];
void dfs(int u,int p){
was[u] = 1;
for(auto to : g[u]){
if(was[to] == 1) continue;
dfs(to,u);
}
top.pb(u);
}
void dfs1(int u){
cnt[cur]++;
cmp[u] = cur;
for(auto to : gr[u]){
if(cmp[to] != 0) continue;
dfs1(to);
}
}
void solve(){
int n,k;
cin >> n >> k;
for(int i = 0; i < n; i++){
int k;
cin >> k;
for(int j = 0; j < k; j++){
int x;
cin >> x;
g[i].pb(x);
gr[x].pb(i);
}
}
for(int i = 0; i < n; i++) if(was[i] != 1)dfs(i,i);
for(int i = n - 1; i >= 0; i--){
if(cmp[top[i]] == 0){
cur++;
dfs1(top[i]);
}
}
int ans = 0;
for(int i = 1; i <= cur; i++) if(cnt[cur] != 1)ans = max(ans,min(cnt[cur],k));
cout << ans;
}
signed main(){
//freopen("time.in", "r", stdin);
//freopen("time.out", "w", stdout);
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
int t1 = 1;
while(t1--){
solve();
}
}
