Given an array of size n, a triplet (a[i], a[j], a[k]) is called a Magic Triplet if a[i] < a[j] < a[k] and i < j < k. Count the number of magic triplets in a given array.

Example 1:

Input: arr = [3, 2, 1]
Output: 0
Explanation: There is no magic triplet.

Example 2:

Input: arr = [1, 2, 3, 4]
Output: 4
Explanation: Fours magic triplets are 
(1, 2, 3), (1, 2, 4), (1, 3, 4) and 
(2, 3, 4).

Your Task:
You don't need to read or print anything. Your task is to complete the function countTriplets() which takes the array nums[] as input parameter and returns the number of magic triplets in the array.

Expected Time Complexity: O(N²)
Expected Space Complexity: O(1)

Constraints:
1 <= length of array <= 1000
1 <= arr[i] <= 100000