Baekjoon 1018号:Bret-force

public void run()
{
    // 크기 입력 받기
    int size_x, size_y;
    String[] board;
    {
        String[] str = readline().split(" ");
        size_x = Integer.parseInt(str[1]);
        size_y = Integer.parseInt(str[0]);
    }

    // 보드판 입력받기
    board = new String[size_y];
    for(int i = 0; i < size_y; i++)
    {
        board[i] = readline();
    }

    // brute force 실행
    int min = 5000;
    for(int i = 0; i <= size_y-8; i++)
    {
        for(int j = 0; j <= size_x-8; j++)
        {
            int num = check(board, j, i);
            if(num < min) min = num;
        }
    }

    // 출력
    print(min);
}
public int check(String[] board, int x_start, int y_start)
{
    // 첫번째가 W 인경우 확인 B인경우 확인 2번 해야함
    int result = 5000;
    boolean isBlack = false;

    for(int n = 0; n < 2; n++)
    {
        isBlack = !isBlack;
        int count = 0;
        for(int i = 0; i < 8; i++)
        {
            for(int j = 0; j < 8; j++)
            {
                if(isBlack)
                {
                    if(board[i+y_start].charAt(j+x_start) == 'W')
                    {
                        //print("is not black");
                        count++;
                    }
                    else
                    {
                        //print("is black");
                    }
                }
                else // isW
                {
                    if(board[i+y_start].charAt(j+x_start) == 'B')
                    {
                        //print("is not white");
                        count++;
                    }
                    else
                    {
                        //print("is white");
                    }
                }
                isBlack = !isBlack;
            }
            isBlack = !isBlack;
        }
        //print(count);
        if(result > count)  result = count;
    }
    return result;
}


public String readline()
{
    try {
        return br.readLine();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return null;
}
public static void print(long num){System.out.println(num);}
public static void print(String str){System.out.println(str);}



public static void main(String[] args) { new Main().run();}