function theLoveLetterMystery($s) {
    // Write your code here
    $abjad = ["a"=>1, "b"=>2, "c"=>3, "d"=>4, "e"=>5, "f"=>6, "g"=>7, "h"=>8, "i"=>9, "j"=>10, "k"=>11, "l"=>12, "m"=>13, "n"=>14, "o"=>15, "p"=>16, "q"=>17, "r"=>18, "s"=>19, "t"=>20, "u"=>21, "v"=>22, "w"=>23, "x"=>24, "y"=>25, "z"=>26];

    $split_s = str_split($s);
    $s_count = count($split_s);
    $separate = $s_count/2;
    $hasil = 0;
    
    if ($s_count % 2 == 0) {
        for ($i = $separate ; $i < $s_count; $i++) {
            $hasil += abs($abjad[$s[$i]] - $abjad[$s[$s_count - 1 - $i]]);
        }
    }
    else {
        for ($i = ceil($separate) ; $i < $s_count; $i++) {
            $hasil += abs($abjad[$s[$i]] - $abjad[$s[$s_count - 1 - $i]]);
        }
    }
    
    return $hasil;
}