#include <cstdio>
#include <iostream>
#include <fstream>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <sstream>
#include <iomanip>
#include <cmath>
#include <cstdlib>
#include <ctype.h>
#include <cstring>
#include <ctime>
#include <cassert>
#include <utility>

using namespace std;

int K, N;
vector<int> v;
vector<int> all, aux;

int main() {
	freopen("interclasari.in", "r", stdin);
	freopen("interclasari.out","w", stdout);

    scanf("%d", &K);
    for(int i = 0; i < K; i++) {
        scanf("%d", &N);
        v.resize(N);
        for(int j = 0; j < N; j++)
            scanf("%d", &v[j]);

        aux.resize(all.size() + N);
        merge(v.begin(), v.end(), all.begin(), all.end(), aux.begin());
        all.resize(all.size() + N);
        copy(aux.begin(), aux.end(), all.begin());
    }

    printf("%d\n", (int)all.size());
    for(size_t i = 0; i < all.size(); i++)
        printf("%d ", all[i]);

	return 0;
}