class Node:
    def __init__(self, data):
        self.data = data
        self.next = None


def build(arr):
    head = None
    for x in reversed(arr):
        node = Node(x)
        node.next = head
        head = node
    return head


def process(head, m):
    if not head:
        return head

    dummy = Node(0)
    dummy.next = head
    prev = dummy
    cur = head
    i = 1

    while cur:
        if i % 2 == 0:
            node = Node(m)
            prev.next = node
            node.next = cur
            prev = cur
            cur = cur.next
            i += 1
        else:
            prev = cur
            cur = cur.next
            i += 1

    return dummy.next


def print_list(h):
    while h:
        print(h.data, end=" ")
        h = h.next
    print()


def print_last_ref(h):
    if not h:
        print("None")
        return
    while h.next:
        h = h.next
    print(h)


while True:
    try:
        print("\n1 - создать список")
        print("2 - обработать")
        print("3 - вывести ссылку на последний элемент")
        print("0 - выход")
        c = input(">> ")

        if c == "1":
            head = build(list(map(int, input().split())))
        elif c == "2":
            m = int(input("M: "))
            head = process(head, m)
            print_list(head)
        elif c == "3":
            print_last_ref(head)
        elif c == "0":
            break
    except:
        print("Ошибка")