#include <stdio.h>
#include <algorithm>
using namespace std;

int k,nk,v[20000005],elem;

int main()
{
    freopen("interclasari.in","r",stdin);
    freopen("interclasari.out","w",stdout);
    scanf("%d",&k);
    int nr;
    for(int i=1;i<=k;i++) {
        scanf("%d",&nk);
        for(int i=1;i<=nk;i++) {
            scanf("%d",&v[elem]);
            elem++;
        }
    }
    sort(v,v+elem);
    printf("%d\n",elem);
    for(int i=0;i<elem;i++)
        printf("%d ",v[i]);
    return 0;
}