php, 50 bytes

Result

WA

Code [DL]

<?= $a=str_split(readline());sort($a);implode($a);

stdin

6004352352795882066882633621928525703379642679212328377956048078372553196568357846218537379635963550

stdout

Array

stderr

PHP Notice:  Array to string conversion in /volume/CODE on line 1

strace