#define _USE_MATH_DEFINES
#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define MT make_tuple
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
#define RT return
#define vv(a,b,c,d) vector<vector<a> >(b,vector<a>(c,d))
#define vvv(a,b,c,d,e) vector<vector<vector<a> > >(b,vv(a,c,d,e))
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(20);

    int N, M;
    while (cin >> N >> M) {
        vector<set<int> > G(N);
        queue<int> Q;

        rep(a, M) {
            int g, r;
            cin >> g >> r;
            g--;
            rep(b, r) {
                int h;
                cin >> h;
                --h;
                G[g].insert(h);
            }
        }

        rep(a, N)if (!sz(G[a]))Q.push(a);

        int re = 0;
        while (sz(Q)) {
            re++;
            int p = Q.front(); Q.pop();
            rep(a, N)if (G[a].count(p)) {
                if (sz(G[a]) == 1) {
                    Q.push(a);
                }
                G[a].erase(p);
            }
        }
        cout << re << endl;
    }
}