width, height, color1 = gets.split
color2 = color1 == 'W' ? 'B' : 'W'
height.to_i.times do |i|
  array = []
  width.to_i.times do |j|
    if j.even?
      array << color1
    else
      array << color2
    end
  end
  array.reverse! if i.odd?
  puts array.join
end