using System;
using System.Linq;

public class P0082 {
    public static void Main() {
        var whc = Console.ReadLine().Trim().Split(' ').ToList();
        var w = int.Parse(whc[0]);
        var h = int.Parse(whc[1]);
        var c = whc[2];
        var a = c == "W" ? "B" : "W";
        for(int i=0; i<h; i++) {
            Console.WriteLine(
                String.Join(
                    ""
                  , Enumerable.Range(0,w).Select(j => (i+j) % 2 == 0 ? c : a)
            ));
        }
    }
}