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$flag = 1; print $flag ? sort 'a'..'z' : sort {$b cmp $a } 'a'..'z';;
a b c d e f g h i j k l m n o p q r s t u v w x y z
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$flag = 0; print $flag ? sort 'a'..'z' : sort {$b cmp $a } 'a'..'z';;
z y x w v u t s r q p o n m l k j i h g f e d c b a