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 and his friends decided to go hiking. Sentence2: While hiking Tom tripped and fell down a cliff. Sentence3: He was injured so his friends called for help. Sentence4: Search and rescue came and saved Tom. Sentence5: After a two weeks in the hospital Tom recovered.
Output:
Search and rescue, His friends, Tom