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: Sam is terrified of flying. Sentence2: He closes his eyes tightly as the plane lifts off the tarmac. Sentence3: His hands clench the armrests throughout the entire flight. Sentence4: He lets out a deep sigh as the plane touches down safely. Sentence5: Sam has conquered his fear once again.
A:
Sam