#include <fstream>
#include <queue>

using namespace std;

priority_queue<int> q;
int k, n;
ifstream f("interclasari.in");
ofstream g("interclasari.out");

int main()
{
    f >> k;
    for (int i = 1;i <= k;i++)
    {
        f >> n;
        for (int j = 1;j <= n;j++)
        {
            int x;
            f >> x;
            q.push(-x);
        }
    }
    g << q.size() << "\n";
    while(!q.empty())
    {
        g << -q.top() << " ";
        q.pop();
    }
    f.close();
    g.close();
    return 0;
}