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: Williams loved cake a lot. Sentence2: He loved it so much that he always ate a little. Sentence3: One day, he noticed he was getting fat. Sentence4: He rushed to the doctor. Sentence5: The doctor told him that eating cake would make him fat.
Output:
Williams, Doctor