#include <bits/stdc++.h>
using namespace std;
int i,j,k,n,t,aux;

struct compare  
 {  
  bool operator()(const int& l, const int& r)  
   {  
    return l > r;  
   }  
 };  

priority_queue <int,vector<int>, compare >  PQ;

int main(void)
{
 ifstream cin("interclasari.in");
 ofstream cout("interclasari.out");
 cin>>t;
 while(t--)
   {
   	cin>>n;
   	for (i=1;i<=n;++i)
   	   {
		cin>>aux; 
		PQ.push(aux);
	   }	 	
   }
 cout<<PQ.size()<<"\n";
 while(PQ.size())
  {
   cout<<PQ.top()<<" ";
   PQ.pop();
  }
 return 0;
}