package main

import (
	"fmt"
)

func main() {
	var w, h int
	var c string
	fmt.Scan(&w, &h, &c)
	wh := make([]string, 2)
	wh[0] = c
	if c == "B"{
		wh[1] = "W"
	}else{
		wh[1] = "B"
	}
	for i:=0; i<h; i++{
		for j:=0; j<w; j++{
			fmt.Print(wh[(i+j)%2])
		}
		fmt.Print("\n")
	}
}