#include <bits/stdc++.h>
using namespace std;
ifstream fin("interclasari.in");
ofstream fout("interclasari.out");
//multiset <long long>ms;
//multiset <long long> :: iterator it;
vector<long long>v[21];
priority_queue<int,vector<int>,greater<int>>pq;
long long k,i,x,m,sum,j;
int main()
{
        fin>>k;
        for(i=1;i<=k;i++)
        {

        fin>>m;sum+=m;
        for(j=1;j<=m;j++)
        {
        fin>>x;
        pq.push(x);


        }



        }





       fout<<pq.size()<<endl;


        while(!pq.empty()){

        fout<<pq.top()<<' ';pq.pop();

        }
    return 0;
}