#include<cstdio>
#include<vector>
#include<algorithm>
using namespace std;
vector<int>v;
int main(){
freopen("interclasari.in","r",stdin);
freopen("interclasari.out","w",stdout);
int k,i,j,n,x;
scanf("%d",&k);
for(i=1;i<=k;i++){
scanf("%d",&n);
for(j=1;j<=n;j++){
scanf("%d",&x);
v.push_back(x);}}
sort(v.begin(),v.end());
printf("%d\n",v.size());
for(i=0;i<v.size();i++)
printf("%d ",v[i]);
return 0;}