#include <fstream>
#include <vector>
using namespace std;
ifstream f("interclasari.in");
ofstream g("interclasari.out");
int n,m;

vector<int> v,sol;
vector<int>::iterator it,k;

int main(void){
    register int i,j,x;

    f>>n;
    for(i=1;i<=n;i++){
        f>>m;
        if(m==0)
            continue;
        it=v.begin();
        for(j=1;j<=m;j++){
            f>>x;
            while(it!=v.end() && x>*it)
                sol.push_back(*it),it++;
            sol.push_back(x);
        }
        while(it!=v.end())
            sol.push_back(*it),it++;
        v.clear();
        for(it=sol.begin();it!=sol.end();it++)
            v.push_back(*it);
        sol.clear();
    }

    g<<v.size()<<"\n";
    for(it=v.begin();it!=v.end();it++)
        g<<*it<<" ";
    f.close();
    g.close();
    return 0;
}