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: May was a teacher at a high school. Sentence2: She had come to hate her job. Sentence3: At finals she gave the students a relatively easy assignment. Sentence4: She was shocked to see there was little effort from the students. Sentence5: May decided to just give everyone a passing grade and be done with it.

Ex Output:
May, The students

Ex Input:
Sentence1: Nicholas was assigned a term paper in his economics class. Sentence2: It was on a topic about which he knew very little. Sentence3: Nicholas spent several days doing in-depth research. Sentence4: He wrote a ten page paper. Sentence5: Nicholas learned about a lot about his new topic.

Ex Output:
Nicholas

Ex Input:
Sentence1: Angela was walking around the pond. Sentence2: She saw a frog resting on the lily pad. Sentence3: She threw a rock at it. Sentence4: She tore a hole in the lily pad! Sentence5: She thought she'd get in trouble, so she ran away.

Ex Output:
Angela, A frog