Given N integers, count the number of pairs of integers whose difference is K.

Input Format

The first line contains N and K. 
The second line contains N numbers of the set. All the N numbers are unique.

Output Format

An integer that tells the number of pairs of integers whose difference is K.

Constraints: 
N≤105 
0<K<109 
Each integer will be greater than 0 and at least K smaller than 231−1.

Sample Input

5 2  
1 5 3 4 2  

Sample Output

3

Explanation

There are 3 pairs of integers in the set with a difference of 2.

Solution

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {
    private static long[] sort(long[] array) {
		int len = array.length;
		for (int i=0; i<len; i++) {
			long buf = array[i];
			for (int j=i; j>=0; j--) {
				if (j>0 && array[j-1] > buf) {
					array[j] = array[j-1];
				} else {
					array[j] = buf;
					break;
				}
			}
		}
		return array;
	}

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        //Scanner in = new Scanner(new File("sample3.txt"));
        int N = in.nextInt();
        long K = in.nextInt();
        long[] array = new long[N];
        
        for (int i=0; i<N; i++) {
        	array[i] = in.nextLong();
        }
        array = sort(array);
        
        int i = 0;
        int count = 0;
        while (i < N) {
        	int j = i+1;
        	while (j < N) {
        		long diff = Math.abs(array[i] - array[j]);
        		if ( diff == K) {
        			count++;
        		}
        		if (diff > K) {
        			break;
        		}
        		j++;
        	}
        	i++;
        }
        System.out.println(count);
    }
}