SPOJ Brasil

You recently wrote a random number generator code for a web application and now you notice that some cracker has cracked it. It now gives numbers at a difference of some given value k more predominantly. You being a hacker decide to write a code that will take in n numbers as input and a value k and find the total number of pairs of numbers whose absolute difference is equal to k, in order to assist you in your random number generator testing.

NOTE: All values fit in the range of a signed integer, n, k ≥ 1

Input

1st line contains n and k.

2nd line contains n numbers of the set. All the n numbers are assured to be distinct.

(Edited: n ≤ 10⁵)

Output

One integer saying the number of pairs of numbers that have a difference of k.

Example

Input:
5 2
1 5 3 4 2

Output:
3