w, h, c = input().split()
w = int(w)
h = int(h)
s = ""
re_s = ""

if c == "W":
  for i in range(w):
    if i % 2 == 0:
      s = s + "W"
    else:
      s = s + "B"
else:
  for i in range(w):
    if i % 2 == 0:
      s = s + "B"
    else:
      s = s + "W"

if not w % 2 == 0:
  for i in s:
    if i == "W":
      re_s = re_s + "B"
    else:
      re_s = re_s + "W"

  for i in range(h):
    if i % 2 == 0:
      print(s)
    else:
      print(re_s)
else:
  for i in range(h):
    if i % 2 == 0:
      print(s)
    else:
      print(s[::-1])