SoftUni - Raindrops - PHP - DvDty

<?php

$amountOfRegions = intval(readline());

$density = floatval(readline());

$regionalCoefficientsSum = 0.000;

while ($amountOfRegions--) {
    $input = explode(" ", readline());
    $raindropsCount = intval($input[0]);
    $squareMeters = intval($input[1]);

    $regionalCoefficientsSum += $raindropsCount / $squareMeters;
}

echo number_format($regionalCoefficientsSum / ($density ? $density : 1), 3, '.', '');