#include <fstream>
#include <algorithm>
#include <stack>
#define N 2000001
#include <set>
using namespace std;
ifstream cin("interclasari.in");
ofstream cout("interclasari.out");
int s[N];
int main()
{
    int n,k,i,j,x,c = 0;
    cin >> k;
    for(i = 1;i <= k;i++){
        cin >> n;
        for(j = 1;j <= n;j++){
            cin >> x;
            s[++c] = x;
        }
    }
    sort(s+1,s+c+1);
    cout << c << "\n";
    for(i = 1;i <= c;i++){
        cout << s[i] << " ";
    }
    return 0;
}