#include <bits/stdc++.h>

using namespace std;

int N, K, x, total, frequence[1000001];

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

    scanf("%d", &N);

    for(int i = 0; i < N; i++)
    {
        scanf("%d", &K);

        for(int i = 0; i < K; i++)
        {
            scanf("%d", &x);

            frequence[x]++;

            total++;
        }

    }

    printf("%d\n", total);

    for(int i = 0; i <= 1000000; i++)
    {
        while(frequence[i]--) printf("%d ", i);
    }

    return 0;
}