Instructions: 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.
Input: Sentence1: Tom bought a brand new puppy for his family. Sentence2: They all agreed that they would help take care of it. Sentence3: After a few months, Tom was the only one taking care of it. Sentence4: He trained it and cared for it all by himself. Sentence5: Ton liked it though and he grew a bond with the dog.
Output:
Puppy, Tom