<?php
$items = [
    ['sort' => 1],
    ['sort' => 3],
    ['sort' => 5],
        ['sort' => 1],
        [
            ['sort' => 8],
            ['sort' => 10],
        ]
    ];
    $sum = 0;
    foreach ($items as $item) {
        $sum += $item['sort'];
    }
    echo $sum;


?>