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.
Q: Sentence1: The weather outside was terribly cold. Sentence2: Sam felt pressure to keep his house warm for his family. Sentence3: He went outside with an ax to get firewood. Sentence4: There weren't any trees big enough to chop down. Sentence5: Sam began to hack away at telephone polls out of desperation.
A:
Sam