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: Dave had been feeling constipated for days. Sentence2: He was having trouble concentrating at work and home. Sentence3: He eventually went to the drug store for help. Sentence4: The pharmacist told him to try some different medications. Sentence5: Dave found magnesium really helped relieve his constipation.
Dave, Pharmacist