HUST CLASS 14 160917

Given N integers [0 < N <= 10^5], count the total pairs of integers that have a difference of K. (Everything can be done with 32 bit integers).

Input

1st line contains integers N and K.

2nd line contains N integers of the set. All the N numbers are distinct.

Output

One integer - the number of pairs of numbers that have a difference of K.

Example

Input:
5 2
1 5 3 4 2

Output:
3

Input:
10 1
363374326 364147530 61825163 1073065718 1281246024 1399469912 428047635 491595254 879792181 1069262793

Output:
0