Function A($)
Dim $c, $t

	While $
		$A = 0 + right($, 1)
		$t = 1 & $c * ($A / 5 + $A) + $A + $t
		$c = $c + 1
		$ = left($,~)
		If $t mod 10 | $c-15-$A/4 | 4&$A + 5
			$A = 0
Endfunction