use strict;
use warnings;

my %parent_id  = ();
my %id_to_name = ();

# Building the tree
while (my $line = <DATA>) {
    chomp $line;
    my ($id,$parent_id,$name) = split /,/, $line;
    $parent_id{$id}    = $parent_id;
    $id_to_name{$id}   = $name;
}

# Dumping the tree
my %name_to_id = reverse %id_to_name;
for my $name (sort keys %name_to_id) {
    my $id        = $name_to_id{$name};
    my $parent_id = $parent_id{$id};
    my @ancestors = ($name);

    while (my $name = $id_to_name{$parent_id}) {
        push @ancestors,$name;
        $parent_id = $parent_id{$parent_id};
    }

    print join(',',@ancestors),"\n"; 
}

__DATA__
15,10,name3
10,#,name1
12,10,name2
5,12,name4
8,5,name5