// No.82 市松模様
package main

import (
	"fmt"
	"strings"
)

func main() {
	const black = "B"
	const white = "W"

	var w, h int
	var c string
	fmt.Scan(&w, &h, &c)

	var pair1, pair2 string
	if c == black {
		pair1 = black + white
		pair2 = white + black
	} else {
		pair1 = white + black
		pair2 = black + white
	}

	var line string
	for i := 0; i < h; i++ {
		// 模様の決定
		if i%2 == 0 {
			line = pair1
		} else {
			line = pair2
		}
		// 列数の決定
		if w%2 == 0 {
			fmt.Println(strings.Repeat(line, int(w/2)))
		} else {
			fmt.Println(strings.Repeat(line, int(w/2)) + string(line[0]))
		}
	}
}