sub anagram {
    my $s = shift;
    my %h1;
    my $cnt = 0;

    if (length($s) % 2) {
        return -1;
    }

    my $s1 = substr($s, 0, length($s) / 2);
    my @s2 = split("", substr($s, length($s) / 2, length($s)));

    
    foreach (split("", $s1)) {
        $h1{$_} += 1;
    }

    foreach my $k (@s2) {
        if (defined($h1{$k}) && $h1{$k} != 0) {
            $h1{$k} -= 1;            
        }
        else {
            $cnt++;
        }        
    }

    return $cnt;
}