<?php
$s = trim(fgets(STDIN));
$s = str_split($s, 1);

$alphabet = [
    'Z' => 0,
    '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,
];

$answer = '';
for($i = 0; $i < count($s); $i++){
    $char = $s[$i];
    $char_num = $alphabet[$char];

    if($i + 1 > 25){
        $char_num = $char_num - (($i + 1) % 26);
    } else {
        $char_num = $char_num - ($i + 1);
    }
    
    foreach($alphabet as $key => $value){
        if($char_num === $value){
            $answer .= $key;
        }
    }
}

echo $answer;