#!/usr/bin/perl -l $_=pop;chop while print,s/.(?=(.))/$&+$1-9*($&+$1>9)/ge |
#!/usr/bin/perl -l print$_|=pop;s/\B.\B/$&$&/g;s/../$&%9||0+$&&&9/ge&&do$0 |
#!/usr/bin/perl -l $_=pop;chop while print,s/.(?=(.))/($c=$&+$1)-9*($c>9)/ge |
#!/usr/bin/perl -l $_=pop;chop while print,s/.(?=(.))/($c=$&+$1)>9?$c-9:$c/ge |