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: Maria went to her first swimming lesson. Sentence2: She got to the pool and met her instructor. Sentence3: Maria then put on a life jacket since she did not know how to swim. Sentence4: Her instructor worked on Maria using her arms and legs to swim. Sentence5: Maria finished her lesson and couldn't wait for the next one.
Output:
Her instructor, Maria