output_description: Print the maximum number of desires that can be satisfied at the same time.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N K
      x_1 y_1 c_1
      x_2 y_2 c_2
      :
      x_N y_N c_N
attempt: n, k = map(int, input().split())
  imos=[[0]*(k*2+1) for _ in range(k*2+1)]
  def kukan(z,  c):
      if c=='B':
          if 0<z<=k:
              return [(0, k-z), (k*2-z, k*2)]
          elif z=0:
              return [(0, k)]
          else:
              return [(k*2-z, k*3-z)]
      else:
          if 0<=z<=k:
              return [(k-z, k*2-z)]
          else:
              return [(0, k*2-z), (k*3-z, k*2)]
  
  for i in range(n):
      x, y, c = input().split()
      x=int(x)%(k*2)
      y=int(y)%(k*2)
      kukanx=kukan(x, c)  
      kukany=kukan(y, c)
      for kx in kukanx:
          for ky in kukany:
              imos[kx[0]][ky[0]]+=1
              imos[kx[0]][ky[1]]-=1
              imos[kx[1]][ky[0]]-=1
              imos[kx[1]][ky[1]]+=1
  def sum_imos(l):
      w=len(l)
      h=len(l[0])
      for i in range(w):
          for j in range(1, h):
              l[i][j]+=l[i][j-1]
      for i in range(1, w):
          for j in range(h):
              l[i][j]+=l[i-1][j]
      return l
  imos=sum_imos(imos)
  print(max(max(imos[i]) for i in range(k*2+1) ))
  
   
problem_description: Statement
  
  AtCoDeer is thinking of painting an infinite two-dimensional grid in a
  _checked pattern of side K_. Here, a checked pattern of side K is a pattern
  where each square is painted black or white so that each connected component
  of each color is a K × K square. Below is an example of a checked pattern of
  side 3:
  
  ![cba927b2484fad94fb5ff7473e9aadef.png](https://img.atcoder.jp/arc089/cba927b2484fad94fb5ff7473e9aadef.png)
  
  AtCoDeer has N desires. The i-th desire is represented by x_i, y_i and c_i. If
  c_i is `B`, it means that he wants to paint the square (x_i,y_i) black; if c_i
  is `W`, he wants to paint the square (x_i,y_i) white. At most how many desires
  can he satisfy at the same time?
samples: [{"input": "4 3\n    0 1 W\n    1 2 W\n    5 3 B\n    5 4 B", "output": "4\n    \n\nHe can satisfy all his desires by painting as shown in the example above.\n\n* * *"}, {"input": "2 1000\n    0 0 B\n    0 1 W", "output": "2\n    \n\n* * *"}, {"input": "6 2\n    1 2 B\n    2 1 W\n    2 2 B\n    1 0 B\n    0 6 W\n    4 5 W", "output": "4"}]