<?php

declare(strict_types=1);

function format(string $name, int $number): string
{
    $splittedNumber = str_split((string) $number);
    $lastNumber = end($splittedNumber);
    $secondToLastNumber = prev($splittedNumber) ?: "0";
    if ($secondToLastNumber === "1") {
        $suffix = "th";
    } else {
        $suffix = match ($lastNumber) {
            "1" => "st",
            "2" => "nd",
            "3" => "rd",
            default => "th",
        };
    }
    return "{$name}, you are the {$number}{$suffix} customer we serve today. Thank you!";
}