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: Every Saturday night my friends go bowling. Sentence2: Last week they invited me. Sentence3: I was so excited to go bowling with them. Sentence4: When we went bowling I did not do very well. Sentence5: Even though I didn't bowl well I had a lot of fun with my friends.
Example Output: I (myself), Friends

Example Input: Sentence1: Tom was at a new job. Sentence2: He didn't like his co workers. Sentence3: They had an important project due soon. Sentence4: Tom put his personal feelings aside. Sentence5: They were able to work well together and get it done.
Example Output: His co workers, Tom

Example Input: Sentence1: Sam was attempting to study at his apartment. Sentence2: His roommate was being way too loud. Sentence3: Sam decided to move to a quieter environment. Sentence4: He drove a few minutes to the coffee shop. Sentence5: Sam was able to study in peace while having a cup of coffee.
Example Output:
Roommate, Sam