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#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

ll meeting_to_day[600600];
vector<ll> nbhs[600600];

vector<pair<ll, char>> q;

void bfs(ll v, ll r) {
    vector<ll> bq;
    bq.push_back(v);
    while(bq.size()) {
        ll u = bq.back();
        bq.pop_back();

        for(auto w: nbhs[u]) {
            bq.push_back(w);
        }

        if(nbhs[u].size() == 0) {
            q.push_back({meeting_to_day[r], 'A'});
            q.push_back({meeting_to_day[u], 'D'});
        }
    }

}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    ll k, n;
    cin >> k >> n;

    vector<ll> roots;
    ll id = 0LL;
    for(id = 1LL; id <= n; id++) {
        meeting_to_day[id] = 1LL;
        roots.push_back(id);
    }

    ll last_id = 1;
    for(ll i = 2LL; i <= k; i++) {
        cin >> n;

        ll new_last_id = id;
        for(int j = 0LL; j < n; j++, id++) {
            ll a;
            cin >> a;

            meeting_to_day[id] = i;

            if(a == 0LL) {
                roots.push_back(id);
            } else {
                nbhs[last_id + a - 1].push_back(id);
            }
        }
        last_id = new_last_id;
    }

    for(auto v: roots) {
        bfs(v, v);
    }

    sort(q.begin(), q.end());

    ll ans = 0LL;
    ll c = 0LL;
    for(auto i: q) {
        if(i.second == 'A') {
            c++;
        } else {
            ans = max(ans, c);
            c--;
        }
    }

    cout << ans << "\n";

    return 0;
}