import strutils

const
  letters = ["B", "W"]

var
  scan = stdin.readLine.split
  w = scan[0].parseInt
  h = scan[1].parseInt
  color = if scan[2] == letters[0]: 0 else: 1

for r in 0.. <h:
  var res:string = ""
  for c in 0.. <w:
    var bit:int = (r+c+color) and 1
    res &= letters[bit]
  echo res