Gold Miner

<?php

$input = readline();
$count = 0;
$goldKarats = [];

while ($input !== 'stop') {
    $gold[] = $input;
    if ($count === 0 || $count % 2 === 0) {
        if (!key_exists($gold[$count], $goldKarats)) {
            $goldKarats[$gold[$count]] = 0;
        }
    } else {
        $goldKarats[$gold[$count - 1]] += $gold[$count];
    }
    $input = readline();
    $count++;
}

foreach ($goldKarats as $gold => $karat) {
    printf("%s -> %sK\n", $gold, $karat);
}