#include<iostream>
#include<set>
#include<algorithm>
#include<vector>
using namespace std;
int main()
{
    int d;
    while(cin>>d)
    {
        set<int>s;
        while(d--)
        {
            int data;
            cin>>data;
            s.insert(data);
        }
        cin>>d;
        while(d--)
        {
            int data;
            cin>>data;
            s.insert(data);
        }
       // sort(s.begin(),s.end(),cmp);
        set<int>::iterator iter;
        iter=s.begin();
        while(iter!=s.end())
        {
            cout<<*iter;
            iter++;
        }
        cout<<endl;
    }
    return 0;
}