import java.util.*;
 
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        long k = scanner.nextLong();
        long[] b = new long[n];
 
        for (int i = 0; i < n; i++) {
            b[i] = scanner.nextLong();
        }
 
        long count = 0;
 
        Arrays.sort(b);
 
        for (int i = 0, j = 0; j < n; j++) {
            long d = b[j] - b[i]; //[i............j]
            while (d > k) {
                i++;
                d = b[j] - b[i];
            }
            count += (j - i + 1);
        }
 
        System.out.println(count - n);
        scanner.close();
    }
}

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MyA0CjEgMyA0

3 4
1 3 4