#include <fstream>
#include <algorithm>
using namespace std;
ifstream cin("interclasari.in");
ofstream cout("interclasari.out");
int i, j, n, m, k, x, v[20000005];
int main(){
   cin>>n;
   for(i=1;i<=n;i++){
        cin>>m;
        for(j=1;j<=m;j++){
            cin>>x;
            v[++k]=x;
        }
   }
   sort(v+1, v+k+1);
   cout<<k<<"\n";
    for(i=1;i<=k;i++){
        cout<<v[i]<<" ";
   }
}