#include <iostream>
#include <fstream>
#include <queue>
using namespace std;
ifstream fin("interclasari.in");
ofstream fout("interclasari.out");
priority_queue <int, vector <int>, greater<int> > v;
int k,i,n,j,x;
int main()
{
    fin>>k;
    for(i=1;i<=k;i++)
    {
        fin>>n;
        for(j=1;j<=n;j++)
        {
            fin>>x;
            v.push(x);
        }
    }
    fout<<v.size()<<"\n";
    while(!v.empty())
    {
        fout<<v.top()<<" ";
        v.pop();
    }
    return 0;
}