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: Donna bought a car last week. Sentence2: The car broke down in the middle of the street. Sentence3: She had the car towed to the mechanic. Sentence4: The mechanic informed her that her car is totaled. Sentence5: She is convinced she purchased a lemon.
Donna, Mechanic