use strict;
use warnings;
use Algorithm::Diff;


my $digest = bless {root => {}, maxLevel => 3};

while (<DATA>) {
    chomp;
    next unless length;
    $digest->add ($_);
}
$digest->mergeTails ();
$digest->print ();

sub add {
    my ($self, $line, $level, $context) = @_;
    $level ||= 1;
    $context ||= $self->{root};
   
    if ($level == $self->{maxLevel} or $line !~ s/(\S*?)\s*\W\s+//) {
        push @{$context->{tails}}, [$line =~ /(\S+)/g];
        return;
    }
   
    my $prefix = $1;
   
    $context->{$prefix} ||= {};
    $context = $context->{$prefix};
    $self->add ($line, 1 + $level, $context);
}


sub mergeTails {
    my ($self, $context) = @_;
    $context ||= $self->{root};

    unless (exists $context->{tails}) {
        $self->mergeTails ($context->{$_}) for keys %$context;
        return;
    }
   
    my @tails = sort {length $a <=> length $b} @{$context->{tails}};
    my @groups;
   
    push @{$groups[@$_]}, $_ for @tails;
    @groups = grep {defined $_} @groups;
   
    for my $group (@groups) {
        my @ref = grep {length} @{$group->[-1]};
        my @org = @ref;
        my $count = 1;
       
        pop @$group;
       
        while (@$group) {
            my @new = @{pop @$group};
            my @diffs = Algorithm::Diff::diff (\@ref, \@new);
           
            for my $change (@diffs) {
                next unless $change->[0][0] eq '-';
                $ref[$change->[0][1]] = '';
            }

            ++$count;
        }

        for (0 .. $#ref) {
            next if length $ref[$_];
            $org[$_] = '*****';
        }
       
        push @{$context->{digest}}, [join (' ', @org), $count];
    }
}


sub print {
    my ($self, $context, $indent) = @_;
    $context ||= $self->{root};
    $indent ||= '';
   
    if (exists $context->{digest}) {
        print "$indent($_->[1]) \t$_->[0]\n"
            for sort {$a->[0] cmp $b->[0]} @{$context->{digest}};
        return;
    }
   
    for (sort keys %$context) {
        print "$indent$_\n";
        $self->print ($context->{$_}, $indent . '    ');
    }
}


__DATA__
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