<?   
function plural_form($n, $form1, $form2, $form5)
{
$n = abs($n) % 100;
$n1 = $n % 10;
if ($n > 10 && $n < 20) return $form5;
if ($n1 > 1 && $n1 < 5) return $form2;
if ($n1 == 1) return $form1;
return $form5;
}  
?>