#include <fstream>
#include <bitset>
using namespace std;
ifstream fin("interclasari.in");
ofstream fout("interclasari.out");
int k,n[21],x,j,N,i,mx;
bitset<90000000>s;
int main()
{fin>>k;
 for(i=1;i<=k;i++)
    {fin>>n[i];
     for(j=1;j<=n[i];j++)
        {fin>>x;
         s[x]=1;
         if(x>mx)mx=x;
        }
        N+=n[i];
    }fout<<N<<"\n";
 for(i=0;i<=mx;i++)
    if(s[i]==1)fout<<i<<" ";
}