use strict;
use warnings;

my %name;
while(my $line =<DATA>)
{
    next unless $line =~ /\S/; #skip blank lines
    chomp $line;
    my ($undef, $markerName,undef,
        undef, $height) = split (/\s+/, $line);         
    $name{$markerName} = $height;    
}

foreach (sort keys %name)
{
   print "$_ => $name{$_}\n";
}  

=prints
a => 55
b => 32
c => 34
=cut


__DATA__
1 a 23 99999 55
4 c 55 8888 34

5 b 45 88888 32