package main

import . "fmt"

func main() {
	var w,h int
	var b string
	Scan(&w,&h,&b)
	x:=[]string{
		b,
		string('W'+'B'-b[0]),
	}
	for i:=0;i<h;i++ {
		for k:=0;k<w;k++ {
			Print(x[(i+k)%2])
		}
		Println()
	}
}