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: Lily was in a bad friendship. Sentence2: She didn't want to be in it anymore. Sentence3: So she decided to not be in it. Sentence4: It was painful. Sentence5: But it was also worth it.
Example Output: Lily

Example Input: Sentence1: Tom was in a hurry to get to work. Sentence2: He didn't have enough time to match his socks. Sentence3: At the office his co-workers made fun of him. Sentence4: His boss questioned his attire as well. Sentence5: Tom never made that mistake again.
Example Output: Boss, Co-workers, Tom

Example Input: Sentence1: Ethan loved playing video games on his mother's iPad. Sentence2: One night he took it to bed with him when his mother wasn't looking. Sentence3: He stayed up all night playing Minecraft. Sentence4: The next day he was so pale his mother thought he was sick. Sentence5: She let him stay home from school and play Minecraft.
Example Output:
His mother, Ethan