package m.shin;
import java.util.Scanner;
public class Con82 {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		int W = s.nextInt() , H = s.nextInt();
		String[] bw = new String[2];
		if(s.next().equals("B")){
			bw[0] = "B";
			bw[1] = "W";
		}else{
			bw[0] = "W";
			bw[1] = "B";
		}
		s.close();

		String ichi = "";
		for(int i = 0;i < H;i++){
			for(int j = 0;j < W;j++){
				ichi += bw[j % 2];
			}
			String a = bw[0];
			bw[0] = bw[1];
			bw[1] = a;
			ichi += "\n";
		}

		System.out.print(ichi);

	}

}