const val COLORS = "RYGB"

fun main(args: Array<String>) {
  val (h, w, d) = readLine()!!.split(" ").map { it.toInt() }
  val board = Array(h, { CharArray(w) })
  for (y in 0 until h) {
    for (x in 0 until w) {
      val s = x + y
      val t = x - y + 2 * d * 1000
      val cs = if ((s % (2 * d)) < d) 0 else 1
      val ct = if ((t % (2 * d)) < d) 0 else 1
      board[y][x] = COLORS[2 * ct + cs]
    }
  }

  for (y in 0 until h) {
    println(String(board[y]))
  }
}
