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: Marcus was playing his guitar at school. Sentence2: His friend Matthew approached him and asked about the music. Sentence3: Soon they were in a heated conversation about their music tastes. Sentence4: The duo decided that they should collaborate on some music. Sentence5: The resulting album was very popular with all of their friends.
Example Output: Marcus, Their friends, Matthew

Example Input: Sentence1: Adam was going hang gliding. Sentence2: He was nervous but excited. Sentence3: He followed his instructions exactly. Sentence4: Then he jumped out and sailed off. Sentence5: He was thrilled to soar on the clouds!
Example Output: Adam

Example Input: Sentence1: I was sitting outside by the pool yesterday. Sentence2: I started to get very thirsty. Sentence3: I didn't know what to do. Sentence4: I immediately ran inside for some water. Sentence5: When I was done I felt better.
Example Output:
I (myself)