import java.util.*;
import java.lang.*;
// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
Set<Integer> set = new TreeSet<>();
int m = sc.nextInt();
// int[] arr1 = new int[m];
for(int i=0; i<m; i++){
// arr1[i] = sc.nextInt();
set.add(sc.nextInt());
}
int n = sc.nextInt();
// int[] arr2 = new int[n];
for(int i=0; i<n; i++){
// arr2[i] = sc.nextInt();
set.add(sc.nextInt());
}
StringBuffer sb = new StringBuffer();
for(Integer i: set){
sb.append(i);
}
System.out.println(sb.toString());
}
}