Instructions: 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.
Input: Sentence1: Allen had never seen a play performed live before. Sentence2: He was reluctant to go when his girlfriend asked him to a performance. Sentence3: He thought the tickets were too expensive and it would be boring. Sentence4: But when they saw the play, Allen was surprised how much he liked it. Sentence5: It was too expensive to do often, but he planned to go sometimes.
Output:
His girlfriend, Allen