using System;

namespace ConsoleApp11
{
    class Program
    {
        static void Main(string[] args)
        {
            int count = 0;

            var input = Console.ReadLine().Split(' ');

            int W = int.Parse(input[0]);
            int H = int.Parse(input[1]);
            string C = input[2];

            for(int i = 0; i < H; i++)
            {
                while (true)
                {
                    if(C == "B")
                    {
                        Console.Write("B");

                        count++;

                        if(count >= W)
                        {
                            break;
                        }

                        Console.Write("W");

                        count++;

                        if(count >= W)
                        {
                            break;
                        }
                    }

                    if(C == "W")
                    {
                        Console.Write("W");

                        count++;

                        if(count >= W)
                        {
                            break;
                        }

                        Console.Write("B");

                        count++;

                        if(count >= W)
                        {
                            break;
                        }
                    }
                }

                if(C == "W")
                {
                    C = "B";
                }
                else if(C == "B")
                {
                    C = "W";
                }

                Console.WriteLine();

                count = 0;
            }

            Console.WriteLine();
        }
    }
}