Help me in solving COINS problem

help
,
1

My issue

How can I perform the addition of very large numbers in PHP. I get an error message when I try to use the bcmath function to do so.

My code

<?php


for($i = 0; $i < 10; $i++)  {
    $n = readline();

    if($n == false) {
        break;
    } else {
        $x = floor($n / 2);
        $y = floor($n / 3);
        $z = floor($n / 4);
        
        $sum = bcadd($x + $y + $z);
        print(max($sum, $n) . PHP_EOL); 
    }
}

Problem Link: COINS Problem - CodeChef