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: Tom was trying to make hamburgers. Sentence2: He found some old meat in the freezer. Sentence3: He wasn't sure if it was still good. Sentence4: Tom noticed a bad smell when he started cooking it. Sentence5: He decided not to risk it.
Tom