write a go solution for Description:
You are given a permutation p of length n and a positive integer k. Consider a permutation q of length n such that for any integers i and j, where 1<=i<j<=n, we have p_{q_i} \le p_{q_j} + k.

Find the minimum possible number of inversions in a permutation q.

A permutation is an array consisting of n distinct integers from 1 to n in arbitrary order. For example, [2,3,1,5,4] is a permutation, but [1,2,2] is not a permutation (2 appears twice in the array) and [1,3,4] is also not a permutation (n=3 but there is 4 in the array).

An inversion in a permutation a is a pair of indices i and j (1<=i,j<=n) such that i<j, but a_i>a_j.

Input Format:
The first line contains two integers n and k (1<=n<=5000, 1<=k<=8).

The second line contains n distinct integers p_1,p_2,ldots,p_n (1<=p_i<=n).

Output Format:
Print the minimum possible number of inversions in the permutation q.

Note:
In the first example, the only permutation is q=[1] (0 inversions). Then p_q_1=1.

In the second example, the only permutation with 1 inversion is q=[1,3,2]. Then p_q_1=2, p_q_2=1, p_q_3=3.

In the third example, one of the possible permutations with 6 inversions is q=[3,4,5,1,2]. Then p_q_1=3, p_q_2=2, p_q_3=1, p_q_4=5, p_q_5=4.. Output only the code with no comments, explanation, or additional text.