t = gets.chomp.split(" ")
w ,h = t[0..1].map{|u|u.to_i}
c = t[2]
d = "W"
if c == "W"
  d = "B"
end
h.times do |n|
  w.times do |m| 
    if((n+m)%2==0)
      print c
    else
      print d
    end
  end
  puts ""
end