<?php
class Army
{
	private array $units = [];
	public function addUnit(Unit $unit): void
	{
		array_push($this->units, $unit);
	}
	public function bombardStrength(): int
	{
		$ret = 0;
		foreach ($this->units as $unit) {
			$ret += $unit->bombardStrength();
		}
		return $ret;
	}
}