///_|_
#include <fstream>
#include <algorithm>
using namespace std;
ifstream in("interclasari.in");
ofstream out("interclasari.out");
int v[20000005];
int main()
{
    int n,x,nr=0;
    in>>n;
    for(int i=1;i<=n;i++){
        in>>x;
        for(int j=1;j<=x;j++)
            in>>v[++nr];
    }
    in.close();
    sort(v+1,v+nr+1);
    out<<nr<<"\n";
    for(int i=1;i<=nr;i++)
        out<<v[i]<<" ";
    out<<"\n";
    out.close();
    return 0;
}