#include <stdio.h>
#include <vector>
#include <algorithm>
using namespace std;
int K, N;
vector<int> v,SOL,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(SOL.size() + N);
        merge(v.begin(), v.end(), SOL.begin(), SOL.end(), aux.begin());
        SOL.resize(SOL.size() + N);
        copy(aux.begin(), aux.end(), SOL.begin());
    }
    printf("%d\n", (int)SOL.size());
    for(int i=0;i<SOL.size();i++)printf("%d ", SOL[i]);
    return 0;
}