Instructions: 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: Nicholas was assigned a term paper in his economics class. Sentence2: It was on a topic about which he knew very little. Sentence3: Nicholas spent several days doing in-depth research. Sentence4: He wrote a ten page paper. Sentence5: Nicholas learned about a lot about his new topic.
Output:
Nicholas