B'You have a stripe of checkered paper of length n . Each cell is either white or black. What is the minimum number of cells that must be recolored from white to black in order to have a segment of k consecutive black cells on the stripe? If the input data is such that a segment of k consecutive black cells already exists, then print 0. The first line contains an integer t ( 1 <= t <= 10^4 ) -- the number of test cases. Next, descriptions of t test cases follow. The first line of the input contains two integers n and k ( 1 <= k <= n <= 2 cdot10^5 ). The second line consists of the letters 'W ' (white) and 'B ' (black). The line length is n . It is guaranteed that the sum of values n does not exceed 2 cdot10^5 . For each of t test cases print an integer -- the minimum number of cells that need to be repainted from white to black in order to have a segment of k consecutive black cells. In the first test case, s ="BBWBW" and k=3 . It is enough to recolor s_3 and get s ="BBBBW". This string contains a segment of length k=3 consisting of the letters 'B '. In the second test case of the example s ="BBWBW" and k=5 . It is enough to recolor s_3 and s_5 and get s ="BBBBB". This string contains a segment of length k=5 consisting of the letters 'B '. In the third test case of the example s ="BBWBW" and k=1 . The string s already contains a segment of length k=1 consisting of the letters 'B '. '...