#include <bits/stdc++.h>
#include <vector>

using namespace std;

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

    int k, n, max_required = 0;
    cin >> k >> n;

    vector<vector<int>> meetings;
    vector<vector<int>> counter;

    meetings.push_back(vector<int>(n, 0));
    counter.push_back(vector<int>(n, 0));

    for (int i = 1; i < k; i++) {
        int count;
        cin >> count;
        meetings.push_back(vector<int>(count));
        counter.push_back(vector<int>(count, 0));
        for (int j = 0; j < count; j++) {
            cin >> meetings[i][j];
        }
    }

    for (int i = k - 1; i >= 0; i--) {
        int current_required = 0;
        for (int j = 0; j < meetings[i].size(); j++) {
            if (counter[i][j] == 0) {
                counter[i][j] = 1;
            }
            if (i >= 1 && meetings[i][j] != 0) {
                counter[i - 1][meetings[i][j] - 1] += counter[i][j];
            }
            current_required += counter[i][j];
        }
        max_required = max(max_required, current_required);
    }

    cout << max_required << endl;

    return 0;
}