#include<fstream>
#include<algorithm>
using namespace std;
ifstream in("interclasari.in");
ofstream out("interclasari.out");

int v[20000009],n,k,poze=0;

void read()
{

    in>>k;
    ++k;
    int i;
    while(--k){
        in>>n;
        for(i = 1 ; i <= n ; i++)
            in>>v[++poze];
    }
    in.close();
}

void write()
{

    out<<poze<<"\n";
    for(int i = 1 ; i <= poze ; i++)
        out<<v[i]<<" ";
    out.close();
}

int main()
{

    read();
    sort(v+1,v+poze);
    write();
    return 0;
}