#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> > :: 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);
        }
    }
    multiset <int> a(v.begin(),v.end());
    fout<<a.size()<<"\n";
    for(itr=a.begin();itr!=a.end();itr++)
    {
        fout<<*itr<<" ";
    }
}