#include <bits/stdc++.h>
#define in "interclasari.in"
#define out "interclasari.out"
using namespace std;
ifstream fin(in);
ofstream fout(out);

priority_queue <int> q;

int k;
int n;

void Citire()
{
    int i,j;
    int x;

    fin >> k;
    for (i = 1; i <= k; i++)
    {
        fin >> n;
        for (j = 1; j <= n; j++)
        {
            fin >> x;
            q.push(-x);
        }
    }
}

void Rezolvare()
{
    fout << q.size() << "\n";
    while (!q.empty())
    {
        fout << -q.top() << " ";
        q.pop();
    }
}

int main()
{
    Citire();
    Rezolvare();

    fin.close();
    fout.close();
    return 0;
}