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: Consider Input: Sentence1: Jim's son is afraid to fly. Sentence2: He's seen too many stories about plane crashes. Sentence3: He can't sleep the night before they are set to fly to Denver. Sentence4: But by the time he gets on the plane he is exhausted. Sentence5: He is so tired that he sleeps all the way through the flight.

Output: Jim's son

Input: Consider Input: Sentence1: Ken had just bought a new computer game. Sentence2: But he could not get it to work! Sentence3: So he called a smart friend over to help him install it. Sentence4: His friend got it figured out in no time. Sentence5: Soon the two boys were gaming together happily!

Output: Ken, Friend

Input: Consider Input: Sentence1: The couple took a romantic trip to Ireland. Sentence2: They saw some amazing castles on cliffs. Sentence3: They toured the most historic castles that were open. Sentence4: The took photos in each place to remember it. Sentence5: The castles would hold a special place in their hearts.
Output: The couple