Given the task definition and input, reply with output. 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: I went to my friend's house for piano lessons. Sentence2: I had a few pieces I was working on. Sentence3: I got feedback early on. Sentence4: I was never good enough to sight read hymns. Sentence5: But I knew I could learn any piece.
I (myself), Friend