#include <fstream>
#include <set>
using namespace std;
ifstream fin("interclasari.in");
ofstream fout("interclasari.out");


int k,n,x;

multiset <int,greater<int> > v;
multiset <int,greater<int> > :: reverse_iterator itr;

int main()
{
    fin>>k;
    for(int i=1;i<=k;i++)
    {
        fin>>n;
        for(int j=1;j<=n;j++)
        {
            fin>>x;
            v.insert(x);
        }
    }

    fout<<v.size()<<"\n";

    for(itr=v.rbegin();itr!=v.rend();itr++)
    {
        fout<<*itr<<" ";
    }
}