#include <bits/stdc++.h>
using namespace std;
ifstream fin("interclasari.in");
ofstream fout("interclasari.out");
int n,m,a[20000001];
int main()
{
    int i,j,k,val,x;
    fin>>m;
    n=0;
    for(i=1;i<=m;i++)
    {
        fin>>k;
        for(j=1;j<=k;j++)
        {
            fin>>x;
            a[++n]=x;
        }
    }
    fout<<n<<"\n";
    sort(a+1,a+n+1);
    for(i=1;i<=n;i++)
        fout<<a[i]<<" ";
    fin.close();
    fout.close();
    return 0;
}