(Program {+(Assignment {+(Identifier)+} {+(If {+(Identifier)+} {+(Identifier)+} {+(Identifier)+})+})+} (If { (Identifier) ->(Identifier) } (Call (Identifier) (Empty)) { (Identifier) ->(Call {+(Identifier)+} {+(Empty)+}) }) {-(Assignment {-(Identifier)-} {-(If {-(Identifier)-} {-(Identifier)-} {-(Identifier)-})-})-})