(function (f, w, h, c)
	h = tonumber(h)
	local s,t = f(w,c)
	for _=2,h,2 do io.write(s,"\n",t,"\n") end
	if h%2~=0 then io.write(s,"\n") end
end)(function (w, c)
	w = tonumber(w)
	local t = c=="B" and "W" or "B"
	if w==1 then return c,t end
	local s = (c..t):rep(bit.rshift(w,1))..(w%2~=0 and c or "")
	return s,s:sub(2)..(w%2~=0 and t or c)
end, io.stdin:read("*l"):match("(%w+)%s(%w+)%s(%w+)"))