import java.util.*;

// 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 in = new Scanner(System.in);
        TreeSet<Integer> tree = new TreeSet<>();
        int n = in.nextInt();
        int[] a = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = in.nextInt();
            tree.add(a[i]);
        }
        int m = in.nextInt();
        int[] b = new int[m];
        for (int i = 0; i < m; i++) {
            b[i] = in.nextInt();
            tree.add(b[i]);
        }
        for (int s : tree) {
            System.out.print(s);
        }
    }
}