#! perl -slw
use strict;
use Time::HiRes qw[ time ];

$|++;

sub uniq{ my %x; @x{@_} = (); keys %x }

my $start = time;
my @uniq = uniq <>;
chomp @uniq;

@uniq = sort{ length $a <=> length $b } @uniq;

my $all = join chr(0), @uniq;
my $p = 0;

for my $x ( @uniq ) {
    $p += 1+ length $x;
    next if 1+ index $all, $x, $p; ## COrrected per LanX below.
    print $x;
}

printf STDERR "Took %.3f\n", time() - $start;