#include<cstdio>
#include<algorithm>
using namespace std;
int n,i,j,k,s,v[5000100];
FILE *f,*g;
int main(){
    f=fopen("interclasari.in","r");
    g=fopen("interclasari.out","w");
    fscanf(f,"%d",&n);
    for(i=1;i<=n;i++){
        fscanf(f,"%d",&k);
        for(j=1;j<=k;j++){
            fscanf(f,"%d",&v[++s]);
        }
    }
    fprintf(g,"%d\n",s);
    sort(v+1,v+s+1);
    for(i=1;i<=s;i++){
        fprintf(g,"%d ",v[i]);
    }







    fclose(f);
    fclose(g);
    return 0;
}