write a go solution for Description:
You are given a number k and a string s of length n, consisting of the characters '.' and '*'. You want to replace some of the '*' characters with 'x' characters so that the following conditions are met:

- The first character '*' in the original string should be replaced with 'x';
- The last character '*' in the original string should be replaced with 'x';
- The distance between two neighboring replaced characters 'x' must not exceed k (more formally, if you replaced characters at positions i and j (i<j) and at positions [i+1,j-1] there is no "x" symbol, then j-i must be no more than k).

For example, if n=7, s=.**.*** and k=3, then the following strings will satisfy the conditions above:

- .xx.*xx;
- .x*.x*x;
- .xx.xxx.

- .**.*xx (the first character '*' should be replaced with 'x');
- .x*.xx* (the last character '*' should be replaced with 'x');
- .x*.*xx (the distance between characters at positions 2 and 6 is greater than k=3).

Given n, k, and s, find the minimum number of '*' characters that must be replaced with 'x' in order to meet the above conditions.

Input Format:
The first line contains one integer t (1<=t<=500). Then t test cases follow.

The first line of each test case contains two integers n and k (1<=k<=n<=50).

The second line of each test case contains a string s of length n, consisting of the characters '.' and '*'.

It is guaranteed that there is at least one '*' in the string s.

It is guaranteed that the distance between any two neighboring '*' characters does not exceed k.

Output Format:
For each test case output the minimum number of '*' characters that must be replaced with 'x' characters in order to satisfy the conditions above.

Note:
None. Output only the code with no comments, explanation, or additional text.