# intentionally no warnings used.
my @array = qw(1 3 4 55 4 3 4 22 1 3 4 3 2 2 3 34);
@array = sort @array;

my $prev;
for (0..$#array) {
    my $i = $array[$_];
    print "$i\n" if $i != $prev && $i != $array[$_+1];
    $prev = $i;
}