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: Sue was a freshman at college and was having a hard time. Sentence2: She was a biology major and the classes were very difficult. Sentence3: She would stay up all night studying and still struggle to pass. Sentence4: Her roommate was also a biology major and ran a study group. Sentence5: She invited Sue to come study with the group to get extra help.
Output:
Sue