#include <bits/stdc++.h>
using namespace std;

int a[20000001];
int main(void){
    ofstream cout("interclasari.out");
    ifstream cin("interclasari.in");
    /// vedem daca putem folosii interclasarea :)
    int k,size1 = 0;
    cin >> k;
    int n;
    //cin >> n;
    for(int kk = 1;kk<=k;kk++){
        cin>>n;
        int x1 =0;
        for(int i = 1;i<=n;i++){
            cin >> x1;
            a[++size1] = x1;
        }
    }
    sort(a+1,a+size1+1);
    cout << size1 << endl;
    for(int i = 1;i<=size1;i++){
        cout << a[i] << ' ';
    }
}