Given an array arr of n positive integers. The task is to swap every i^th element of the array with (i+2)^th element.

Note: When passing array to function, we basically pass the reference to the array. More details here. We'll learn more about pointers and references in upcoming module.

Example:

Input:
n = 5
arr[] = 1 2 3 4 5
Output:
3 4 5 2 1
Explanation:
Swapping 1 and 3, makes the array 3 2 1 4 5.
Now, swapping 2 and 4, makes the array 
3 4 1 2 5. Again,swapping 1 and 5, makes the 
array 3 4 5 2 1.

Your Task:
Your task is to complete the function swapElements(), which should swap each ith element with (i+2)^th element. No need to print or return the array.
 

Expected Time Complexity: O(n)
Expected Auxilary Space: O(1)

Constraints:
1 <= N <= 10⁶
1 <= A_i <= 10⁶