class A
  def initialize
    w, h, c = gets.chomp.split(' ')

    o = (c == 'W')? 'B' : 'W'

    w = w.to_i
    h = h.to_i

    even_str  = ((c+o) * w).slice(0,w)
    odd_str   = ((o+c) * w).slice(0,w)

    h.times do |i|
      puts (i.even?)? even_str : odd_str
    end
  end
end

A.new