import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int w = sc.nextInt();
        int h = sc.nextInt();
        char[] dis = new char[]{'B', 'W'};
        int add;
        if (sc.next().charAt(0) == 'B') {
            add = 0;
        } else {
            add = 1;
        }
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                sb.append(dis[(i + j + add) % 2]);
            }
            sb.append("\n");
        }
        System.out.print(sb);
    }
}