import java.util.Scanner;

public class Main82 {
	public static void main(String[] args) {
		Main82 p = new Main82();
	}

	public Main82() {
		Scanner sc = new Scanner(System.in);
		int W = sc.nextInt();
		int H = sc.nextInt();
		char[] c = new char[2];
		c[0] = sc.next().charAt(0);
		c[1] = c[0]=='W' ? 'B' : 'W';
		solve(W, H, c);
	}

	public void solve(int w, int h, char[] c) {
		
		for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				System.out.print((c[(i+j)%2]));
			}
			System.out.println();
		}
	}

}