using System;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        // No.82 市松模様

        string whc = Console.ReadLine();
        int W = int.Parse(whc.Split(' ')[0]);
        int H = int.Parse(whc.Split(' ')[1]);
        string C = whc.Split(' ')[2];

        string[] bw = { "B", "W" };
        int fromBW = 0;
        if (C.Equals("W")) fromBW++;

        // 縦
        for (int i = 0; i < H; i++)
        {
            // 横
            for (int j = i + fromBW; j < W + i + fromBW; j++)
                Console.Write(bw[j % 2]);

            Console.WriteLine();
        }
    }
}