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: Sam was making homemade fries for the first time. Sentence2: He had stepped out of the kitchen when he smelled smoke. Sentence3: He ran into the kitchen and saw an oil fire. Sentence4: He remembered to smother it instead of using water. Sentence5: Luckily, the fire was subdued and didn't make too much damage.

Output: Sam

Input: Consider Input: Sentence1: I am Chinese. Sentence2: One day I was sitting on the bench in front of my building. Sentence3: A young man came by and said I looked like his father. Sentence4: He was white, however, as was his father. Sentence5: He said I just looked like his dad.

Output: I (myself), Young man

Input: Consider Input: Sentence1: Samantha wanted to buy a gift for her boyfriend, Doug. Sentence2: She had a lot of money, but wasn't sure what to buy. Sentence3: Samantha asked Doug's friend for advice. Sentence4: Doug's friend told Samantha that Doug needed a new watch. Sentence5: Samantha bought Doug a watch, and Doug was happily surprised.
Output: Samantha, Doug's friend, Doug