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: Lou was helping his dad weed around the bushes. Sentence2: All of a sudden he felt a sharp sting. Sentence3: He looked at his arm and saw there were bees on it. Sentence4: He had accidentally disturbed their nest. Sentence5: He ran off as quickly as he could before he was swarmed.
Output:
Dad, Lou