def sort(nb1, nb2):
    if len(nb1) == 0: return nb2
    elif len(nb2) == 0: return nb1
    elif nb1[0] < nb2[0]: return [nb1[0]] + sort(nb1[1:], nb2)
    else: return [nb2[0]] + sort(nb1, nb2[1:])
    
number1 = [4,13,6,6,2,7,2,9,29]
number2 = [4,13,6,6,2,7,2,9,29]
number1.sort()
number2.sort()
print(sort(number1, number2))