while True:
    try:
        input()
        l1 = input().split()
        input()
        l2 = input().split()
    except EOFError:
        break
    l1 = [int(x) for x in l1]
    l2 = [int(x) for x in l2]
    l1.extend(l2)
    l1 = list(set(l1))
    l1.sort()
    print("".join([str(x) for x in l1]))