Holding_company = String Company . Company = "company" String Employee Employee "{"Company_list "}". Company_list : Nonempty | Empty *common* . Nonempty = Company Company_list . Empty = . Employee : Manager | Worker *common* "salary"Salary . Manager = "manager". Worker = "worker". Salary = Currency . Currency = Integer . CountingVisitor = Integer . SummingVisitor = Currency . CondTravVisitor = boolean. Main = .