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

priority_queue<int> Q;
int n;

ifstream fin("interclasari.in");
ofstream fout("interclasari.out");
int main()
{
    int k,i,x;

    fin>>n;

    while (n--)
    {
        fin>>k;
        for (i=0;i<k;++i)
        {
            fin>>x;
            Q.push(-x);
        }
    }
    fout<<Q.size()<<'\n';

    while (!Q.empty())
    {
        fout<<-Q.top()<<" ";
        Q.pop();
    }

    return 0;
}