Given the task definition and input, reply with output. 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.

Sentence1: Lisa was waiting for an important letter. Sentence2: She checked the mail and there was an envelope addressed to her. Sentence3: Lisa nervously opened the envelope. Sentence4: It was the news she was waiting for. Sentence5: The letter was an acceptance letter to college!
Lisa