#include<stdio.h>
using namespace std;
int frec[5000000];
int main()
{
    int K,N,a,s=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",&a);
            frec[a]++;s++;
        }
    }
    printf("%d\n",s);
    for(int i=0;i<=5000000;++i){
        for(int j=1;j<=frec[i];j++) printf("%d ",i);
    }
    fclose(stdin);fclose(stdout);
    return 0;
}