#!/usr/bin/perl -w

use strict;

my $input = shift;
my %seen;

my $order=1;
foreach my $dir ( split /:/, $input ) {
        $seen{$dir} = $order++ unless ($seen{$dir})  ;
}
my $output =  join( ':',  sort { $seen{$a} <=> $seen{$b} } keys(%seen));
print $output . "n";