How to access class const dynamically?

Question

class InputCheck
{
   const NOT_INPUT = "%sRequired";

   public function inList ($msg = null)
   {
     print_r(self::$msg);exit;
   }
}

(new InputCheck())->inList('NOT_INPUT');

In this class I have defined a constant with the name NOT_INPUT. One of the methods accepts a string which contains the name of that constant. How can I use this value to access the class constant dynamically?