#include<fstream>
#include<algorithm>
using namespace std;
ifstream in("interclasari.in");
ofstream out("interclasari.out");
int k,j,l,n,i,v[2000003];
int main()
{
in>>n;
for(i=1;i<=n;i++)
{
    in>>k;
    for(j=1;j<=k;j++)
        in>>v[++l];
}
sort(v+1,v+l+1);
out<<l<<'\n';
for(i=1;i<=l;i++)
out<<v[i]<<' ';
out<<'\n';
out.close();
return 0;

}