Угол между часовой и минутной стрелками

<?php
$line = trim(fgets(STDIN));
[$hours, $minutes] = explode(':', $line);

if ($hours > 12) {
	$hours = $hours - 12;
}

$hoursHandAngle = $hours * 360 / 12 + $minutes * 360 / 12 / 60;
$minutesHandAngle = $minutes * 360 / 60;

$angle = abs($hoursHandAngle - $minutesHandAngle);

echo $angle > 180 
	? 360 - $angle
	: $angle;