Swap Even And Odd Indices

Swap values at even and odd indices in place. Example: [1,2,3,4] => [2,1,4,3]

Your task

Implement this function:

def swap_even_and_odd_indices(l: list) -> None:

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

This function changes its argument in place and returns nothing; the updated l is what gets printed.

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

Example

Input

[1, 2, 3, 4]

Output

[2, 1, 4, 3]