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: Maude always used old maps to find her way while driving. Sentence2: But this time she couldn't find her target. Sentence3: Maude pulled her phone and found the location using GPS. Sentence4: And as she exited her car, she threw her old map away. Sentence5: From now on, she'd use her phone to find her way.
Example Output: Maude

Example Input: Sentence1: Jeb wanted to make the football team. Sentence2: He practiced every day. Sentence3: He ran as fast as he could. Sentence4: He could catch well. Sentence5: He made the team and was happy!
Example Output: Jeb

Example Input: Sentence1: Mike and Tony bought a baby duck at the spring festival. Sentence2: It was decided that Mike was going to keep the duck at night. Sentence3: Tony came and pick the duck up one morning. Sentence4: He never returned the duck that night. Sentence5: The next day he told Mike that the duck had died.
Example Output:
Tony, Mike, Duck