You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
In this task, you're given a story (which contains five sentences only). Your task is to find all the characters which are available in the given story.

Sentence1: My dog was bored. Sentence2: I was working all day so I couldn't spend time with him. Sentence3: When I finished work I decided to play with my dog. Sentence4: He was so happy to finally have some fun! Sentence5: Alas, he fell sick and died.
Solution: I (myself), Dog
Why? There is only two characters in given story, i.e., I (myself) and dog.

New input: Sentence1: Gary went for a bike ride on the river trail. Sentence2: He saw an object on the ground so he stopped to look. Sentence3: The object was a wallet with a picture and a driver's license inside. Sentence4: Gary sent the wallet through the mail to the address on the license. Sentence5: The man called Gary to thank him for sending his wallet to him.
Solution:
Man, Gary