#include <cstdio>
#include <queue>
using namespace std;
FILE *fin=fopen ("interclasari.in","r");
FILE *fout=fopen ("interclasari.out","w");
int n, i, a,k;
priority_queue<int,  vector<int> , greater<int> > h;

int main()
{
    fscanf(fin,"%d",&k);
    for(;k>0;k--)
    {
        fscanf(fin,"%d",&n);
        for(i=1;i<=n;i++)
        {
            fscanf(fin,"%d",&a);
            h.push(a);
        }
    }
    fprintf (fout,"%d\n",h.size());
    while(!h.empty())
    {
        fprintf (fout,"%d ",h.top());
        h.pop();
    }
    return 0;
}