#include <cstdio>
#include <queue>

using namespace std;
FILE *fin=fopen("interclasari.in", "r");
FILE *fout=fopen("interclasari.out", "w");

int n, nr, a;
priority_queue<int, vector<int>, greater<int> > hp;

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