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: Gareth loved animals. Sentence2: His favourite animal was the Rhino. Sentence3: He felt so sad that they were going extinct. Sentence4: Gareth decided to move to Africa to help Rhinos. Sentence5: He adopted a Rhino called Mahimba who became his best friend.
Output:
Mahimba, Gareth