#include <iostream>
#include <fstream>
#include <queue>
#define DIM 200000
using namespace std;

int k;
priority_queue<int> pq;

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