Son has an array of n elements a[1], a[2] ... a[n] and an integer k, today that he wants to count how many pairs of (a[i], a[j]) (1 <= i < j <= n) have been content with: max (a [i], a [j]) - min (a [i], a [j]) = k. Could you help Son?

Input

- First line, integer n and k (n<=200, k<=100)

- Second line, n integer a[1], a[2] ... a[n] (a[i]<=100)

Output

- Number of pair.

Example

Input:
4 1
1 2 3 4

Output:
3