import java.util.Arrays;
import java.util.Scanner;
 
public class ZCO15002 {
 
//    Variation count
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int k = sc.nextInt();
        int count = 0;
        int[] array = new int[n];
 
        for(int i=0;i<n;i++){
            array[i] = sc.nextInt();
        }
 
        Arrays.sort(array);
 
        for(int i = 0,j=1;i<n-1 && j<n;){
            if(array[j]-array[i]>=k){
                count = count + n - j;
                i++;
            }else{