#include <fstream>
#include <algorithm>
#include <vector>

using namespace std;

ifstream f ("interclasari.in");
ofstream g ("interclasari.out");

vector < int > v;

int n, m, i, j, x, lg;

int main()
{
 f >> n;
  for (i=1; i<=n; i++)
  {
      f >> m;
       for (j=1; j<=m; j++)
       {
           f >> x;
           v.push_back(x);
       }
  }
 lg = v.size();

 sort(v.begin(), v.end());

  g << lg << '\n';

  for (i=0; i<lg; i++)
    g << v[i] << " ";

    return 0;
}