import java.util.*;
public class Main {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
int len1 = Integer.valueOf(scan.nextLine().trim());
String[] numsStr1 = scan.nextLine().split(" ");
int len2 = Integer.valueOf(scan.nextLine().trim());
String[] numsStr2 = scan.nextLine().split(" ");
HashSet<Integer> hashSet = new HashSet<>();
for (int i = 0; i < len1; i++) {
hashSet.add(Integer.valueOf(numsStr1[i]));
}
for (int i = 0; i < len2; i++) {
hashSet.add(Integer.valueOf(numsStr2[i]));
}
int[] nums = hashSet.stream().mapToInt(Integer::intValue).toArray();
Arrays.sort(nums);
// heapSort(nums);
/// quickSort(nums);
for (int num : nums) {
System.out.print(num);
}
}
public static void heapSort(int[] nums) {
if (null == nums || nums.length < 2) {
return;
}
for (int i = 0; i < nums.length; i++) {
heapInsert(nums, i);
}
int heapSize = nums.length;
swap(nums, 0, --heapSize);
while (heapSize > 0) {
heapify(nums, 0, heapSize);
swap(nums, 0, --heapSize);
}
}
public static void heapInsert(int[] nums, int index) {
while (nums[index] > nums[(index - 1) / 2]) {
swap(nums, index, (index - 1) / 2);
index = (index - 1) / 2;
}
}
public static void heapify(int[] nums, int index, int heapSize) {
int left = index * 2 + 1;
while (left < heapSize) {
int largest = left + 1 < heapSize && nums[left + 1] > nums[left] ? left + 1 : left;
largest = nums[largest] > nums[index] ? largest : index;
if (largest == index) {
break;
}
swap(nums, index, largest);
index = largest;
left = index * 2 + 1;
}
}
public static void swap(int[] nums, int p1, int p2) {
int tmp = nums[p1];
nums[p1] = nums[p2];
nums[p2] = tmp;
}
public static void quickSort(int[] nums) {
if (null == nums || nums.length < 2) {
return;
}
process(nums, 0, nums.length - 1);
}
public static void process(int[] nums, int start, int end) {
if (start >= end) {
return;
}
int l = start - 1;
int r = end + 1;
int p = start;
int val = nums[end];
while (p < r) {
if (nums[p] < val) {
swap(nums, p++, ++l);
} else if (nums[p] > val) {
swap(nums, p, --r);
} else {
p++;
}
}
process(nums, start, l);
process(nums, r, end);
}
}