Height Difference

A class is choosing actors for the school play "Laurel and Hardy" - a comedy duo famous for their large difference in height. The heights of all $n$ students are known, and a duo looks right exactly when the difference in height of its two members is exactly $r$.

Your task is to count in how many ways two students can be picked so that their height difference is exactly $r$. Two students with equal heights are still two different students - pairs are counted by who is in them, not by their heights.

Input

The first line contains a single integer $t$ - the number of testcases.

• The first line of each testcase contains two integers $n$ and $r$ - the number of students and the required height difference.
• The next line contains $n$ integers $a_0,a_1,\dots ,a_{n-1}$ - the heights of the students in millimeters. Heights can repeat.

Output

For every testcase print a single line with the number of pairs of students whose height difference is exactly $r$.

Example

2
5 2350
15745 18095 15745 16234 13395
4 1
7 7 8 9

4
3

In the first testcase the pairs are: the first and the second student, the first and the fifth, the second and the third, and the third and the fifth. In the second testcase both students of height $7$ pair with the one of height $8$, and the one of height $8$ pairs with the one of height $9$.

Constraints

$1\le t\le 1000$
$1\le n\le 2\cdot 10^5$
$1\le a_i\le 10^9$
$1\le r\le 10^9$
$n_1+n_2+\dots +n_t\le 2\cdot 10^5$

This problem was adapted, with permission, from Razlika visina, authored by Društvo matematičara Srbije and Fondacija Petlja.