W, H, C = gets.chomp.split
width = W.to_i

# H行分出力する
H.to_i.times do |i|
    case C
    when "B" then
        str = (i + 1).odd? ? "BW" : "WB"
    when "W" then
        str = (i + 1).odd? ? "WB" : "BW"
    end
    puts (str * width)[0, width]
end