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.

Example Input: Sentence1: Simon invited his friend Joey over for a play-date. Sentence2: He was looking forward to playing Minecraft with his friend. Sentence3: Right before Joey arrived, the internet went out. Sentence4: Simon tried resetting the router, but it didn't help. Sentence5: Simon and Joey played outside until the router was back online.
Example Output: Simon, Joey

Example Input: Sentence1: Jacob noticed his dog was whining. Sentence2: Jacob investigated and found his dog's leg hurt. Sentence3: He took the dog to see the vet. Sentence4: The vet made a cast to set the hurt leg. Sentence5: Within a few weeks, Jacob and his dog were playing again!
Example Output: Jacob, Vet, Dog

Example Input: Sentence1: The store was running a special. Sentence2: It gave customers $5 off of any shoe purchase. Sentence3: The mom decided now was a good time to buy shoes for the family. Sentence4: They all got new sandals and tennis shoes. Sentence5: The mom was happy to have saved some money.
Example Output:
Customers, Mom, The family