Harmonious Pairs of Houses

You are given N houses in a row, each painted in a certain color. The colors are represented by integers. You are also given an integer K, which defines the target difference between the colors. A pair of houses (i, j) (with i < j) is considered harmonious if
\( |\text{color}_i - \text{color}_j| = K \). Your task is to count the total number of harmonious pairs among the houses.

Note: Each harmonious pair should be counted exactly once.

Example:
For example, with N = 5, K = 3 and colors [1, 5, 2, 2, 8], the harmonious pairs are formed by the indices corresponding to the pairs of colors (1,4), (3,4) and (2,5) (based on 1-indexing), hence the answer is 3.

inputFormat

The input is read from stdin and consists of two lines:

1. The first line contains two space-separated integers N and K, where N is the number of houses and K is the target difference between house colors.
2. The second line contains N space-separated integers representing the color of each house.

outputFormat

Output a single integer to stdout — the number of harmonious pairs of houses.

5 3
1 5 2 2 8

3