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#include <vector>
#include <iostream>

using namespace std;

struct Node {
    int value;
    bool visited;
    std::vector<Node*> children;

    Node() : value(0), visited(false) {}
};

void dfs(Node *node) {
    if (node == nullptr || node->visited) return;

    node->visited = true;
    
    if (node->children.size() == 0) {
        node->value = 1;
        return;
    } else {
        for (Node* child : node->children) {
            dfs(child);
        }
        int sum = 0;
        for (Node* child : node->children) {
            sum += child->value;
        }
        node->value = sum;
    }    
}

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

    int k, n;
    int confs, conf;

    cin >> k >> n;

    vector<vector<Node*>> conf_days(k);

    // Day 1
    conf_days[0].reserve(n);
    for (int i = 0; i < n; i++) {
        conf_days[0].push_back(new Node());
    }

    // Next days
    for (int i = 1; i < k; i++) {
        cin >> confs;
        conf_days[i].reserve(confs);
        for (int j = 0; j < confs; j++) {
            cin >> conf;
            auto node = new Node();
            conf_days[i].push_back(node);
            if (conf > 0) {
                conf_days[i - 1][conf - 1]->children.push_back(node);
            }
        }
    }

    for (int i = 0; i < k; i++) {
        for (Node* node : conf_days[i]) {
            dfs(node);
        }
    }

    int max_sum = 0;
    for (int i = 0; i < k; i++) {
        int sum = 0;
        for (Node* node : conf_days[i]) {
            sum += node->value;
        }
        if (sum > max_sum) {
            max_sum = sum;
        }
    }

    cout << max_sum << endl;

    return 0;
}