W, H, C1 = gets.chomp.split
intw = W.to_i
inth = H.to_i

C2 = C1 == "B" ? "W" : "B"

(1..inth).each do |n|
  output = []
  if n.odd?
    (1..intw).each do |i|
      if i.odd?
        output.push(C1)
      else
        output.push(C2)
      end
    end
  else
    (1..intw).each do |i|
      if i.odd?
        output.push(C2)
      else
        output.push(C1)
      end
    end
  end
  puts output.join
end