import java.util.Scanner;
public class No82 {
	public static void main (String[] args){
	Scanner sc =new Scanner(System.in);
	int w=sc.nextInt() ,h=sc.nextInt();
	boolean c=sc.next().charAt(0)=='W';
	for(int i=c?1:0;i<h+(c?1:0);i++){
	for(int j=0;j<w;j++)
	System.out.print(j%2==0^i%2==0?'W':'B');
	System.out.println();
	}
	}
}