// Source: https://usaco.guide/general/io

#include <bits/stdc++.h>
#include <fstream>
#include <queue>
using namespace std;
ifstream f("interclasari.in");
ofstream g("interclasari.out");
vector <int> v[25];
vector <int> t;
priority_queue<pair<int,int>,vector<pair<int,int>>,greater<pair<int,int>>> pq;
int n,k,x,s;
int main() {
	f>>k;
    for(int j=0;j<k;j++)
    {
        f>>n;
        if(n)
        {
            for(int i=1;i<=n;i++)
        {
            f>>x;
            v[j].push_back(x);
        }
        t.push_back(0);
        pq.push({v[j][0],j});
        s+=n;
        }
    }
    g<<s<<'\n';
    while(!pq.empty())
    {
        int val=pq.top().first;
        int sir=pq.top().second;
        g<<val<<' ';
        pq.pop();
        t[sir]++;
        if(t[sir]<v[sir].size())
        {
            pq.push({v[sir][t[sir]],sir});
        }
    }


}