(W, H, C) = map(str, input().split())
W = int(W)
H = int(H)

if C == 'B':
  S = ['B', 'W']
else:
  S = ['W', 'B']

for h in range(H):
  L = ""
  for w in range(W):
    L += S[(h+w)%2]
  print(L)