#include <fstream>
#include <set>

using namespace std;

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

int n, k;
multiset<int> s;

int main() {
    fin >> k;
    for (int i = 0; i < k; ++ i) {
        fin >> n;
        for (int j = 0; j < n; ++ j) {
            int temp;
            fin >> temp;
            s.insert(temp);
        }
    }
    fin.close();
    fout << s.size() << "\n";
    for (auto &it : s)
        fout << it << " ";
    fout << "\n";
    fout.close();
    return 0;
}