Function s($x)
	Dim $j,$,$a[2*$x]
	For $j = 0 to 2*$x
		$a[$j] = $j-$x
	Next

	$s = d(0,$a)

	For $ = 1 to $x
		For $j = 1 to $
			$a = c($j,$a)
			$s = d($s,$a)
		Next
		$=$+($x>$)
		For $j = -1 to -$ step -1
			$a = c($j,$a)
			$s = d($s,$a)
		Next
	Next
	If 0= $x MOD 2
	 $=1
	 gosub n
	endif
	For $ = 1 to $x
		If $x MOD 2
		 gosub n
		 $=$+($x>$)
		endif
		If $ < $x
			For $j = -$ to -$x step -1
				$a = c($j,$a)
				$s = d($s,$a)
			Next
		endif
		If 0= $x MOD 2
		 $=$+($x>$)
		 gosub n
		endif
	Next
	$s=Split($s,a)
exit
:n
	For $j = $ to $x
		$a = c($j,$a)
		$s = d($s,$a)
	Next
return
EndFunction

Function c($a,$)
	$c = AScan($,$a)
	$[AScan($,0)]=$a
	$[$c]=0
	$c = $
EndFunction

Function d($,$s)
	If $
		$d = $ + a
	EndIf
	For Each $ in $s
		$d= $d + SubStr("W B",1+($=)+2*($>),1)
EndFunction