#include <cstdio>
#include <algorithm>
#include <list>
using namespace std;
FILE*fin=fopen("interclasari.in","r");
FILE*fout=fopen("interclasari.out","w");
int i,j,N,M,x;
list<int> v;
int main()
{

    list<int>::iterator it=v.begin();
    fscanf(fin,"%d%d",&N,&M);
    for (j=1;j<=M;++j)
            fscanf(fin,"%d",&x),v.push_back(x);
    for (i=1;i<N;++i)
        {
            it=v.begin();
            fscanf(fin,"%d",&M);
            for (j=1;j<=M;++j)
                {
                    fscanf(fin,"%d",&x);
                    while (*it<x)++it;
                    v.insert(it,x);
                }
        }
       fprintf(fout,"%d\n",v.size());
    for (it=v.begin();it!=v.end();++it)
        fprintf(fout,"%d ",*it);
    return 0;
}