Copy the exact code from the instructions into the editor and run it by clicking «Run».

```php
<?php

print_r('Hello, World!');
```

Note: If you write `heLLo, woRld!` instead of `Hello, World!`, it will be considered different text because upper and lower case letters are different characters. _Case is important!_ This rule affects almost everything in coding, so make sure you get used to paying close attention to the case at all times.
