#include <fstream>
#include <queue>

using namespace std;

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

int k, n, x;
priority_queue<int, vector<int>, greater<int>> Q;

int main() {
    fin >> k;
    while(k > 0) {
        fin >> n;
        for(int i = 1; i <= n; i++) {
            fin >> x;
            Q.push(x);
        }
        k--;
    }
    fin.close();
    fout << Q.size() << "\n";
    while(!Q.empty()) {
        fout << Q.top() << " ";
        Q.pop();
    }
    return 0;
}