using System;
using System.Collections.Generic;
using System.Linq;

class Yuki0082
{
    static int w, h;
    static char c;

    static void Solve()
    {
        string cells;
        if(c == 'W') cells = "WB";
        else cells = "BW";

        for(var i = 0; i != h; ++i) {
            for(var j = 0; j != w; ++j) {
                if(i % 2 == 0) {
                    Console.Write(j % 2 == 0 ? cells[0] : cells[1]);
                }
                else {
                    Console.Write(j % 2 == 0 ? cells[1] : cells[0]);
                }
            }
            Console.WriteLine();
        }
    }

    static void Scan()
    {
        var buf = Console.ReadLine().Split();
        w = int.Parse(buf[0]);
        h = int.Parse(buf[1]);
        c = buf[2][0];
    }

    static void Main()
    {
        Scan();
        Solve();
    }
}