func main()
	var ss: [][]char :: cui@input().split(" ")
	var W: int :: ss[0].toInt(&)
	var H: int :: ss[1].toInt(&)
	var C: char :: ss[2][0]
	var cc: []char :: #[2]char
	do cc[0] :: C
	do cc[1] :: C = 'B' ?('W', 'B')
	
	for h(1, H)
		var line: []char :: #[W]char
		for w(1, W)
			do line[w - 1] :: cc[(h + w) % 2]
		end for
		do cui@print("\{line}\n")
	end for
end func