#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;
ifstream f("interclasari.in");
ofstream g("interclasari.out");

int n,k;
priority_queue<int, vector<int>, greater<int>> q;
int main()
{
    f>>k;
    for(int i=1;i<=k;i++)
    {
        f>>n;
        for(int j=1;j<=n;j++)
        {
            int x;
            f>>x;
            q.push(x);
        }
    }
    g<<q.size()<<'\n';
    while(!q.empty())
    {
        g<<q.top()<<' ';
        q.pop();
    }
    return 0;
}