using System;
using System.IO;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Numerics;
using System.Diagnostics;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using static System.Math;
using static System.Console;


namespace yukicoder
{
    class Program
    {
        static void Main()
        {
            var t = Console.ReadLine().Split().ToArray();
            var w = int.Parse(t[0]);
            var h = int.Parse(t[1]);
            var c = t[2];
            var str = c;

            for (var i = 0; i < h; i++)
            {
                for (var j = 0; j < w; j++)
                {
                    if (j == 0)
                    {
                        continue;
                    }

                    if (str[j-1] == 'B')
                    {
                        str += 'W';
                    }
                    else
                    {
                        str += 'B';
                    }
                }

                Console.WriteLine(str);

                if(str[0] == 'B')
                {
                    str = "W";
                }
                else
                {
                    str = "B";
                }
            }
        }
        
    }
}