<?php
$str = trim(fgets(STDIN));
$s_s = str_split($str);
$alp = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
foreach($s_s as $k => $v) {
    if ($k > strlen($str)) {
        break;
    }
    $pls = strpos($alp,$v);
    $pls -= $k+1;
    while($pls < 0) {
        $pls += 26;
    }
    echo $alp[$pls];
}
echo PHP_EOL;