#include <iostream>
#include <fstream>
#include <queue>
#include <algorithm>

using namespace std;
/*
#define DEBUG 1
#if DEBUG
std::ifstream fin("input.in");
#else
#define fin std::fin
#endif
*/

ifstream fin("interclasari.in");
ofstream fout("interclasari.out");

int n,k;
priority_queue<int>pq;

int main()
{
    fin>>n;
    for(int i = 1; i <= n; i++)
    {
        fin>>k;
        for(int j = 1; j <= k; j++)
        {
            int x;
            fin>>x;
            pq.push(-x);
        }
    }
    fout<<pq.size()<<"\n";
    while(pq.empty() == false)
    {
        fout<<-pq.top()<<" ";
        pq.pop();
    }
}