content: import java.io.*;
  import java.math.*;
  import java.security.*;
  import java.text.*;
  import java.util.*;
  import java.util.concurrent.*;
  import java.util.regex.*;
  
  public class Solution {
  
    // Complete the beautifulTriplets function below.
    static int beautifulTriplets(int d, int[] arr) {
      HashMap<Integer, Integer> map = new HashMap<>();
      for (int i = 0; i < arr.length; i++) {
        if (map.containsKey(arr[i])) {
          map.put(arr[i], map.get(arr[i]) + 1);
        } else {
          map.put(arr[i], 1);
        }
      }
  
      int counter = 0;
      // i < j < k
      // find = d + a[i]
      for (int i = 0; i < arr.length; i++) {
        if (i == 0 || arr[i] != arr[i - 1]) {
          int j = d + arr[i];
          int k = d + j;
          if (map.containsKey(j) && map.containsKey(k)) {
            counter += map.get(arr[i]) * map.get(j) * map.get(k);
          }
        }
      }
  
      return counter;
    }
  
    private static final Scanner scanner = new Scanner(System.in);
  
    public static void main(String[] args) throws IOException {
      BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));
  
      String[] nd = scanner.nextLine().split(" ");
  
      int n = Integer.parseInt(nd[0]);
  
      int d = Integer.parseInt(nd[1]);
  
      int[] arr = new int[n];
  
      String[] arrItems = scanner.nextLine().split(" ");
      scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");
  
      for (int i = 0; i < n; i++) {
        int arrItem = Integer.parseInt(arrItems[i]);
        arr[i] = arrItem;
      }
  
      int result = beautifulTriplets(d, arr);
  
      bufferedWriter.write(String.valueOf(result));
      bufferedWriter.newLine();
  
      bufferedWriter.close();
  
      scanner.close();
    }
  }
  