<?php
header("Content-Type: application/json; charset=utf-8");

$letter = $_GET["letter"] ?? "";
$text   = $_POST["text"] ?? "";

$letter = strtolower($letter);
$count = 0;

for ($i = 0; $i < strlen($text); $i++) {
    if (strtolower($text[$i]) === $letter) {
        $count++;
    }
}

echo json_encode(["letter" => $letter, "count" => $count]);
?>