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: Jason grew up riding motorcycles. Sentence2: He won his first motorcycle race at the age of 13. Sentence3: He kept racing and improving. Sentence4: Kawasaki sponsored him at the age of seventeen. Sentence5: Jason said that gave him to confidence to win the motocross.
Example Output: Kawasaki, Jason

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: Brad had a desire to be a salesman for an international company. Sentence2: He went to school and got a business degree. Sentence3: After school he was offered a good job traveling the world. Sentence4: Brad has spent the last ten years traveling around Europe. Sentence5: He had decided to get a job in the States to be closer to his family.
Example Output:
International company, Family, Brad