w, h, c = gets.chomp.split
w = w.to_i
h = h.to_i
bw = 'BW'

h.times do |y|
  w.times do |x|
    j = 0
    if c == 'B'
      j = (x + y) % 2
    else
      j = (x + y + 1) % 2
    end
    print bw[j]
  end
  puts
end