#!perl -l $_=pop;print,s@.(?=(.))@$&+$1-9*($&+$1>9)@ge,s@.$@@while//
#!perl $_=pop;s@.(?=(.))@print$&;$&+$1-9*($&+$1>9)@ge,s@.$@!print$&,$/@e while//
#!perl -l @"=split$,,pop;do{print@";$/=shift@"}while@"=map{$;=$/;($;+=$/=$_)-9*($;>9)}@"