#include <bits/stdc++.h>
using namespace std;
ifstream fin("interclasari.in");
ofstream fout("interclasari.out");
priority_queue<int>q;
int n,k;
int main()
{
    int i,j,x;
    fin>>k;
    for(i=1;i<=k;i++)
    {
        fin>>n;
        for(j=1;j<=n;j++)
        {
            fin>>x;
            q.push(-x);
        }
    }
    fout<<q.size()<<"\n";
    while(!q.empty())
    {
        x=-q.top();
        fout<<x<<" ";
        q.pop();
    }
    fin.close();
    fout.close();
    return 0;
}