import java.util.*;
public class Main {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int a = in.nextInt();
Set<Integer> ts = new TreeSet<>();
for(int i = 0; i<a; i++){
ts.add(in.nextInt());
}
int b = in.nextInt();
for(int i = 0; i<b; i++){
ts.add(in.nextInt());
}
for(Integer i : ts){
System.out.print(i);
}
}
}