#include<stdio.h>
#include<algorithm>
using namespace std;
int v[5000005];
int main()
{
    int K,N,el=0;
    freopen("interclasari.in","r",stdin);
    freopen("interclasari.out","w",stdout);
    scanf("%d",&K);
    for( ; K ; --K ){
        scanf("%d",&N);
        for( ; N ; N--){
            scanf("%d",&v[++el]);
        }
    }
    sort(v+1,v+1+el);
    printf("%d\n",el);
    for(int i=1;i<=el;++i)
        printf("%d ",v[i]);
    fclose(stdin);fclose(stdout);
    return 0;
}