<?php
$str="abcdefghijklmnopqrstuvwxyz";
$ret = "";
$n=5;
$n=$n-1;
for($i = 0, $l = strlen($str); $i < $l; ++$i) {
if (97 <= $c && $c < 123) {
$ret.= chr(($c + $n + 7) % 26 + 97); } else if(65 <= $c && $c < 91) {
$ret.= chr(($c + $n + 13) % 26 + 65); } else {
$ret.= $str[$i];
}
}
echo $ret;
?>
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