#include <bits/stdc++.h>

using namespace std;

ifstream fin("interclasari.in");
ofstream fout("interclasari.out");

priority_queue<int, vector<int>, greater<int> > pq;
int k,n,x;

int main()
{
    fin >> k;
    for (int i=0; i<k; i++)
    {
        fin >> n;
        for (int j=0; j<n; j++)
        {
            fin >> x;
            pq.push(x);
        }
    }
    fout << pq.size() << '\n';
    while (!pq.empty())
    {
        fout << pq.top() << " ";
        pq.pop();
    }
    return 0;
}