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.

Ex Input:
Sentence1: Simy heard her mom speaking to her grandma about a lost letter. Sentence2: She asked her mom what happened. Sentence3: Her mom said her grandma had lost a special letter from her grandpa. Sentence4: Simy felt sad but soon forgot as she played. Sentence5: While putting her toys away she found the letter on a toy shelf.

Ex Output:
Simy, Grandpa, Mom, Grandma

Ex Input:
Sentence1: Marie was stuck in traffic and playing a game on her phone. Sentence2: Someone tapped on her window and she recognized a cop. Sentence3: He told her to stop playing and pay attention. Sentence4: She apologized and pocketed her phone. Sentence5: She regretted it as it took an hour for the traffic to move again.

Ex Output:
Cop, Marie

Ex Input:
Sentence1: Martin liked looking for things to buy. Sentence2: He had no money however. Sentence3: So he got a job at a retail place. Sentence4: He made some money by working. Sentence5: And he bought the stuff he needed.

Ex Output:
Martin