using System;

public class Program {
	static string GetPattern (string c, int w) {
		string pattern = "";
		while (w > 0) {
			pattern += c;
			c = ChangeCollor(c);
			w--;
		}
		return pattern;
	}
	
	static string ChangeCollor (string c) {
		if (c.Equals("B")) {
				return "W";
		} else {
				return "B";
		}
	}
	
	public static void Main(string[] args) {
		string[] s = Console.ReadLine().Split(' ');
		int w = int.Parse(s[0]);
		int h = int.Parse(s[1]);
		string c = s[2];
		for (int i = 0; i < h; i++) {
			Console.WriteLine(GetPattern(c, w));
			c = ChangeCollor(c);
		}
	}
}