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

class Magatro
{
    static void Main()
    {
        int W, H;
        string c;
        string[] s = Console.ReadLine().Split(' ');
        W = int.Parse(s[0]);
        H = int.Parse(s[1]);
        c = s[2];
        string b = c == "B" ? "W" : "B";
        for(int i = 0; i < H; i++)
        {
            for(int j = 0; j < W; j++)
            {
                if (j % 2 == 0)
                {
                    Console.Write(c);

                }
                else
                {
                    Console.Write(b);
                }
            }
            Console.WriteLine();
            string q = b;
            b = c;
            c = q;
        }
      
    }
}