w,h,c = map(str, input().split())

cc = []
if c == 'W':
  cc.append('W')
  cc.append('B')
else:
  cc.append('B')
  cc.append('W')

for hh in range(int(h)):
  for ww in range(int(w)):
    sys.stdout.write(cc[(ww + hh) % 2])
  print()