#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

my %tree=();

# baum erstellen
while(my $line=<DATA>)
{
  chomp($line);
  $line=~s/^\s+//;
  $line=~s/\s+$//;
  my @elm=split(/\s+/,$line);
  my $ref=\\%tree;
  $ref=\$$ref->{$_} for(@elm);
  $$ref={} unless($$ref);
}

# baum darstellen
print create(\%tree);

sub create
{
  my $tree=shift;
  my $deep=shift || '';
  my $line=shift || [];
  my $ret='';
  for my $key (sort keys(%$tree))
  {
    my @in=(@$line,$key);
    my $ref=$tree->{$key};
    if(keys(%$ref))
    {
      $ret.=qq($deep+@in<span id=").join('',@in).qq(">\n);
      $ret.=create($ref,"$deep    ",\@in);
      chomp($ret);
      $ret.="</span>\n";
    }
    else
    { $ret.="$deep@in\n"; }
  }
  return $ret;
}

__DATA__
A
  A A
  A B
  A C
  A D
B
  B A
  B B
  B C
C
  C A
  C B
  C C
  C D
  C E
D
  D A
    D A A
    D A B
    D A C
    D A D
  D B
  D C
  D D
    D D A
    D D B
    D D C
    D D D
E
  E A
  E B
F
  F A
  F B
  F C
  F D
  F E
  F F
  F G
  F H
  F I
  F J
  F K
  F L
  F M
  F N
  F O
  F P
  F Q