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 ran into an old teacher after high school. Sentence2: She smiled and asked how old I was. Sentence3: When I told her, she began to tear up a little. Sentence4: She said she was happy I had survived. Sentence5: I stood there in shock, not realizing my teachers had known my past.
I (myself), Old teacher