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: David had never baked on his own before. Sentence2: He was determined to impress his girlfriend, though. Sentence3: David spent all morning searching for recipes until he found one. Sentence4: He gathered his ingredients and tried all afternoon to get it right. Sentence5: The souffles may have been burnt, but his girlfriend didn't mind.
Girlfriend, David