Reverse Each Half

Write a function reverse_first_and_last_halves(items) that reverses the first half of the list items and the second half of items, in place. Split the list at index len(items) // 2; when the length is odd the extra element belongs to the second half. The function returns nothing.

Example

items = [1, 2, 3, 4]
reverse_first_and_last_halves(items)
items  ->  [2, 1, 4, 3]

Your task

Implement this function:

def reverse_first_and_last_halves(items: list) -> None:

Write the function only — the arguments are read for you and the return value is printed automatically.

Arguments arrive as one Python literal per line, in this order: items.

Example

Input

[1, 2, 3, 4]

Output

[2, 1, 4, 3]