package main

import "fmt"

func toggle(c string) string {
	if c == "B" {
		return "W"
	}
	return "B"
}

func main() {
	var W, H int
	var C string
	fmt.Scan(&W, &H, &C)
	for i := 0; i < H; i++ {
		for j := 0; j < W; j++ {
			fmt.Print(C)
			C = toggle(C)
			if j == W-1 && j%2 == 1 {
				C = toggle(C)
			}
		}
		fmt.Println()
	}
}