class Damen

	def initialize
		print "n = "
		n = gets.to_i

		if n < 4
			puts "Ungueltiges n -- setze n = 4."
			n = 4
		end

		if n > 26
			puts "Ungueltiges n -- setze n = 26."
			n = 26
		end

		print "\n"

		@max_n = n

		@damen = []
		n.times {
			@damen += [0]
		}

		@loesungen = 0
	end


	def bedroht (n)
		for i in 1..n
			m = n - i
			if @damen[n] == @damen[m] or @damen[n] == @damen[m] - i or @damen[n] == @damen[m] + i
				return TRUE
			end
		end
		return FALSE
	end


	def dame (n)
		while @damen[n] < @max_n
			@damen[n] += 1
			if not bedroht(n)
				if n < @max_n - 1
					m = n + 1
					@damen[m] = 0
					dame(m)

				else
					print_loesung
				end
			end
		end

		return FALSE
	end


	def print_loesung
		for i in 0...@damen.length
			buchstabe = (65 + i).chr
			zahl = @damen[i]
			dame = i + 1

			print "Dame #{dame}: #{buchstabe}#{zahl}\n"
		end

		@loesungen += 1

		print "\n"
		#exit
	end


	def loese
		dame(0)
		puts "#@loesungen Loesungen"
	end

end


dame = Damen.new
dame.loese