You will be given a definition of a task first, then some input 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: Becky went to the zoo with her friend. Sentence2: They walked to the back of the zoo. Sentence3: They saw Chimpanzees at the back of the zoo. Sentence4: Becky made a funny face and danced in front of the Chimp. Sentence5: The Chimp responded by defecating and tossing feces at Becky.
Output:
Friends, Becky's friend, Becky, Chimpanzees