#include <iostream>
#include <fstream>
#include <queue>
using namespace std;

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

int K;
priority_queue<int> C;

int main()
{
    fin>>K;
    int n,x;
    for(int i=0; i<K; i++)
    {
        fin>>n;
        for(int i=0; i<n; i++)
        {
            fin>>x;
            C.push(-x);
        }
    }
    fout<<C.size()<<'\n';
    while(!C.empty())
    {
        fout<<-C.top()<<" ";
        C.pop();
    }
    return 0;
}