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