#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream in("interclasari.in");
ofstream out("interclasari.out");
priority_queue <int> Q;
vector <int> a[21];
int k,n,i,j,x;
int main()
{
    in>>k;
    for (i=1;i<=k;++i)
    {
        in>>n;
        for (j=1;j<=n;++j)
        {
            in>>x;
            Q.push(-x);
        }
    }
    out<<Q.size()<<"\n";
    while (Q.size())
    {
        out<<-Q.top()<<" ";
        Q.pop();
    }
}