write a go solution for Description:
There are n chips arranged in a circle, numbered from 1 to n.

Initially each chip has black or white color. Then k iterations occur. During each iteration the chips change their colors according to the following rules. For each chip i, three chips are considered: chip i itself and two its neighbours. If the number of white chips among these three is greater than the number of black chips among these three chips, then the chip i becomes white. Otherwise, the chip i becomes black.

Note that for each i from 2 to (n-1) two neighbouring chips have numbers (i-1) and (i+1). The neighbours for the chip i=1 are n and 2. The neighbours of i=n are (n-1) and 1.

The following picture describes one iteration with n=6. The chips 1, 3 and 4 are initially black, and the chips 2, 5 and 6 are white. After the iteration 2, 3 and 4 become black, and 1, 5 and 6 become white.

Your task is to determine the color of each chip after k iterations.

Input Format:
The first line contains two integers n and k (3<=n<=200,000,1<=k<=10^9) — the number of chips and the number of iterations, respectively.

The second line contains a string consisting of n characters "W" and "B". If the i-th character is "W", then the i-th chip is white initially. If the i-th character is "B", then the i-th chip is black initially.

Output Format:
Print a string consisting of n characters "W" and "B". If after k iterations the i-th chip is white, then the i-th character should be "W". Otherwise the i-th character should be "B".

Note:
The first example is described in the statement.

The second example: "WBWBWBW" arrow "WWBWBWW" arrow "WWWBWWW" arrow "WWWWWWW". So all chips become white.

The third example: "BWBWBW" arrow "WBWBWB" arrow "BWBWBW" arrow "WBWBWB" arrow "BWBWBW".. Output only the code with no comments, explanation, or additional text.