Definition: 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: 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