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: Consider Input: Sentence1: Bob love to eat steak. Sentence2: He wants to get steak for an upcoming barbeque. Sentence3: He went to the store but he couldn't find any steak. Sentence4: He continued searching but he still didn't find any steak. Sentence5: His son brought enough steak for everyone for the barbeque.

Output: Bob

Input: Consider Input: Sentence1: Fred was going to make sure he didn't end up like his dad. Sentence2: His dad abused his mom and never provided for his family. Sentence3: Fred found a good job and got married. Sentence4: He supported his family and never abused them. Sentence5: Fred was proud of his own accomplishments.

Output: His mom, His dad, His family, Fred

Input: Consider Input: Sentence1: For years, Martin has been trying to think of the next big invention. Sentence2: Finally, he had a breakthrough. Sentence3: Martin built a prototype of a bowl that separates the cereal and milk. Sentence4: He pitched his idea to several flatware companies. Sentence5: The executives rejected Martin's new invention.
Output: Flatware companies, Executives, Martin