(Statements {+(Assignment {+(Statements {+(Identifier)+} {+(Identifier)+})+} {+(Statements {+(Integer)+} {+(Integer)+})+})+} (Assignment { (Identifier) ->(Identifier) } (Integer)) {+(Assignment {+(Identifier)+} {+(Statements {+(Integer)+} {+(Integer)+})+})+} {-(Assignment {-(Statements {-(Identifier)-} {-(Identifier)-})-} {-(Statements {-(Integer)-} {-(Integer)-})-})-} {-(Assignment {-(Identifier)-} {-(Statements {-(Integer)-} {-(Integer)-})-})-})