import java.io.*;

// 処理
class Process {
    private int    W;
    private int    H;
    private String C;

    Process(int W, int H, String C) {
        this.W = W;
        this.H = H;
        this.C = C;
    }

    String getResult() {
        var result = new StringBuffer("");
        
        for(int i = 0; i < H; i++) {
            for(int j = 0; j < W; j++) {
                switch(C) {
                    case "B":
                        result.append(((i + j) % 2 == 0) ? "B" : "W");
                        break;

                    case "W":
                        result.append(((i + j) % 2 == 0) ? "W" : "B");
                        break;
                } 
            }
            
            result.append("\n");
        }

        return result.toString();
    }
}

public class Main {
    public static void main(String[] args) throws IOException {
        var bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        var printWriter    = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));

        // 入力
        String[] input = bufferedReader.readLine().trim().split("[ ]+");
        int W = Integer.parseInt(input[0]);
        int H = Integer.parseInt(input[1]);

        // 出力
        printWriter.println((new Process(W, H, input[2])).getResult());

        bufferedReader.close();
        printWriter.close();
    }
}