#!/usr/bin/perl -l $_=pop;{print,s,.,$"=$&+$;;$;=$&;$`?$">9?$"-9:$":"",ge,$_&&redo}
#!/usr/bin/perl -l $_=pop;{print;s/./$x=$&+$o;$o=$&;$-[0]?$x>9?$x-9:$x:""/ge;$_&&redo}