package no082;

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int w = sc.nextInt();
		int h = sc.nextInt();
		char c = sc.next().charAt(0);
		int k = c == 'B' ? 0 : 1;
		for(int i=0;i<h;i++) {
			for(int j=0;j<w;j++) {
				System.out.print((i+j+k) % 2 == 0 ? 'B' : 'W');
			}
			System.out.println();
		}
	}

}