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: It was a very windy day. Sentence2: The weather was perfect for kite flying. Sentence3: Cal loosed his kite into the air and watched it soar. Sentence4: He ran across the field but soon felt a jolt in his string. Sentence5: The kite got stuck in a tree.
Output:
Cal