<?php

class Movie
{
    private $title;
    private $studio;
    private $rating;

    public function __construct(string $title, string $studio, string $rating)
    {
        $this->title = $title;
        $this->studio = $studio;
        $this->rating = $rating;
    }

    public function getTitle(): string
    {
        return $this->title;
    }

    public function getStudio(): string
    {
        return $this->studio;
    }

    public function getRating(): string
    {
        return $this->rating;
    }
}

class MoviesManager
{
    private $movies;

    public function __construct(array $movies)
    {
        $this->movies = $movies;
    }

    public function getTitles(): array
    {
        $titles = [];

        foreach ($this->movies as $movie)
        {
            $titles[] = $movie->getTitle();
        }

        return $titles;
    }

    public function getPG(): array
    {
        $pgs = [];

        foreach ($this->movies as $movie)
        {
            $pgs[] = $movie->getRating();
        }

        return $pgs;
    }

    public function getPG13()
    {
        $pgs = [];

        foreach ($this->movies as $movie)
        {
            if ($movie->getRating() === 'PG13')
            {
                $pgs[] = $movie->getTitle();
            }
        }

        return $pgs;
    }
}

$movies = [
    new Movie('Casino Royale', 'Eon Productions', 'PG13'),
    new Movie('Glass', 'Buena Vista International', 'PG13'),
    new Movie('Spider-Man: Into the Spider-Verse', 'Columbia Pictures', 'PG'),
];

$moviesManager = new MoviesManager($movies);

echo implode('|', $moviesManager->getPG13());