#include <fstream>
#include <queue>

using namespace std;

ifstream in("interclasari.in");
ofstream out("interclasari.out");

const int NMAX = 1000000;
const int KMAX = 20;

struct cmp {
    bool operator() ( const int &a, const int &b ) {
        return ( a > b );
    }
};

priority_queue <int, vector <int>, cmp> Hp;

int main() {
    int N,K;
    in >> N;
    for( int i = 1;  i <= N;  ++i ) {
        in >> K;
        for( int j = 1;  j <= K;  ++j ) {
            int nr;  in >> nr;
            Hp.push( nr );
        }
    }
    out << Hp.size() << '\n';
    while( !Hp.empty() ) {
        out << Hp.top() << ' ';
        Hp.pop();
    }
    return 0;
}