#!/usr/bin/perl -w

use strict;

my $nest = 0;
while( my $line = <> )
{
   chomp $line;
   foreach my $c (unpack 'C*', $line)
   {
      $c = chr($c);
      if( $c eq '[' )
      {
         $nest++;
      }
      if( $c eq ' ')
      {
         print $nest < 0 ? '_' : ' ';
      }
      else
      {
         print $nest < 9 ? $nest < 0 ? '-'
                                     : $nest
                         : '9';
      }
      if( $c eq ']' )
      {
         $nest--;
      }
   }
   print "\n";
}