object Main {
  def opposite(c: Char): Char = 
    if (c == 'W') 'B' else 'W'

  def rep(n: Int, c: Char): Char = 
    if (n <= 1) c else rep(n-1, opposite(c))

  def main(args: Array[String]) {
    val sc = new java.util.Scanner(System.in)
    val W, H = sc.nextInt
    var c = sc.next.charAt(0)    

    for (i <- 1 to H) {
      // val s = Iterator.iterate(rep(i, c)) { e => opposite(e) }.take(W)
      val s = Iterator.iterate(rep(i, c))(opposite).take(W)
      println(s.mkString)
    }
  }
}