using System;

public class Hello
{
    public static string bb, ww, bbb, www;
    static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var w = int.Parse(line[0]);
        var h = int.Parse(line[1]);
        makebc();
        bbb = bb.Substring(0, w);
        www = ww.Substring(0, w);
        var c = line[2];
        getAns(w, h, c);
    }
    static void makebc()
    {
        var t = "BW"; var t2 = "WB";
        bb = "";
        ww = "";
        for (int i = 0; i < 25; i++)
        {
            bb += t;
            ww += t2;
        }
    }
    static void getAns(int w, int h, string c)
    {
        var bw = c;
        for (int i = 0; i < h; i++)
        {
            Console.WriteLine(bw == "B"? bbb:www);
            bw = bw == "B" ? "W" : "B";
        }
    }
}