import java.util.*;

public class Solution {

    public static void main(String[] args) {
        Scanner inr = new Scanner(System.in);
        int n = inr.nextInt(), k = inr.nextInt();
        int[] num = new int[n];
        for (int i = 0; i < n; i++) num[i] = inr.nextInt();
        Arrays.sort(num);
        int count = 0;
        for (int i = 0; i < n; i++) {
            for (int j = i + 1; j < n; j++) {
                int diff = num[j] - num[i];
                if (diff == k) count++;
                if (diff > k) break;
            }
        }
        System.out.println(count);
    }
}