Bubble Sort - 2

Determine the number of swaps the bubble sort algorithm performs to sort a given array in ascending order.

Input

The first line contains the integer N (1 ≤ N ≤ 1000), representing the number of elements in the array. The second line provides the array itself. It is guaranteed that all elements in the array are distinct and their absolute values do not exceed 10^9.

Output

Output a single integer, which is the total number of swaps performed by the bubble sort.

Examples