#include <fstream>

#define Max_Size 1000009

using namespace std;

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

int N, K, nr_el_sol;

int A[Max_Size], B[Max_Size * 20], Sol[Max_Size * 20];

int main()
{
    f >> K;
    int k = 0;

    for(int t = 1; t <= K; ++t)
    {
        f >> N;

        int i, j;
        k = 0;

        for(i = 1; i <= N; ++i) f >> A[i];

        for(i = 1, j = 1; i <= N && j <= nr_el_sol;)
            if(A[i] <= Sol[j])
            {
                B[++k] = A[i];
                ++i;
            }
            else
            if(A[i] > Sol[j])
            {
                B[++k] = Sol[j];
                ++j;
            }

        for(; j <= nr_el_sol; ++j)  B[++k] = Sol[j];
        for(; i <= N; ++i)  B[++k] = A[i];

        nr_el_sol += N;

        for(i = 1; i <= nr_el_sol; ++i) Sol[i] = B[i];
    }

    g << nr_el_sol << '\n';

    for(int i = 1; i <= nr_el_sol; ++i) g << Sol[i] << ' ';
}