You are given a paragraph, with numbered sentences, and a question. Write the numbers of the sentences needed to answer the given question. Separate multiple sentence numbers with a comma (", "). E.g. "1, 2" would be the correct response if Sent 1 and Sent 2 are needed to answer the given question (do not include sentences that contain no information that is necessary to answer the question). Sort the sentence numbers in an increasing order (i.e., '1, 2', instead of '2, 1'). Your answer should not contain anything than the sentence numbers separated by a comma (e.g. '1, 2, 3, 4'). The given question requires more than one sentence to answer. So, your answer must contain at least one comma (", ").

Example Input: Paragraph- Sent 1: The Golden Heian Era: The geomancers in 794 decided that Heian-kyo (modern Kyoto) would be an auspicious site for the imperial family.
Sent 2: It was indeeduntil 1869.
Sent 3: Grants of tax-free land over the years had been made to Buddhist temples and members of the court aristocracy.
Sent 4: The most powerful families thus carved out for themselves whole regions that were to become the fiefdoms of Japanese feudalism.
Sent 5: By the end of the eighth century the clans had created a hierarchy of shiki, or rights, from the highest to the lowest ranks of society.
Sent 6: The aristocrat or court patron lent his prestige to a powerful provincial proprietor, who employed a competent estate-manager to oversee smallholders, who in turn worked their farms with dependent laborers.
Sent 7: This elaborate structure of interdependent rights and obligations was to serve Japanese society right into the 20th century.
Sent 8: Meanwhile, Heian court life blossomed in an effusion of aesthetic expression.
Sent 9: Princes and princesses judged the merits of birds, insects, flowers, roots, or seashells.
Sent 10: Literary party games held in ornate palace gardens required each guest to compose a small poem as his wine cup floated toward him along a miniature winding channel of water.
Sent 11: Expeditions were organized to the best viewing points for the first spring cherry blossoms, and special pavilions were built to watch the rising of the full moon.
Sent 12: Every gesture, from the most banal opening of an umbrella to the sublimest act of lovemaking, had its appropriate ceremonial.
Sent 13: Conversation often took the form of elegant exchanges of improvised verse.
Sent 14: The changing role of Chinese culture in Japanese life was epitomized in the language itself.
Sent 15: In the absence of an indigenous alphabet, Japanese scholars had with the greatest difficulty tried to adapt the complex ideograms of monosyllabic Chinese to the essentially polysyllabic Japanese.
Sent 16: Thus developed the katakana system used as a vehicle for writing Buddhist names and concepts.
Sent 17: After rival Fujiwara factions had been struggling for years to gain control of the imperial throne, they turned to the Taira and Minamoto armies in 1156 to wage the four-year war that heralded the end of the golden age of the Heian court.
Sent 18: The Taira, controlling the region along the Inland Sea, defeated the Minamoto armies based in the Kanto province east of the capital.
Question: What lead to the development of katakana system?.
Example Output: 15, 16.

Example Input: Paragraph- Sent 1: One day Billy and Sandy went to the neighborhood fair.
Sent 2: They were so exited because this year Bob the clown was going to be there.
Sent 3: They had heard a lot about Bob the clown, he was funny and knew a lot of balloon tricks.
Sent 4: He always made the kids laugh and gave out small prizes to many of the children at the fair.
Sent 5: Billy and Sandy had even heard that sometimes Bob the clown would give out free cotton candy and candy apples.
Sent 6: They had waited all year and were so excited.
Sent 7: They did all their chores and cleaned their rooms so they could go to the fair.
Sent 8: When they got to the fair they were so happy to see that Bob the clown was handing out cotton candy and candy apples.
Sent 9: Billy and Sandy waited in line and then once it was their turn Billy got a balloon in the shape of a dog and Sandy got a big bag of cotton candy.
Sent 10: They were both happy and could not wait to tell their friends all about Bob the clown.
Question: Where Billy and Sandy happy after seeing Bob the clown?.
Example Output: 9, 10.

Example Input: Paragraph- Sent 1: You approach the door of a friend.
Sent 2: What is the first thing you do?
Sent 3: Of course, you wipe your feet.
Sent 4: You are a thoughtful visitor.
Sent 5: Fortunately, there is a piece of carpet to wipe your shoes.
Sent 6: Too bad your caring comes at a price.
Sent 7: You now reach out to touch the brass knocker on the door.
Sent 8: A spark appears between you and the door.
Sent 9: You feel an electric shock.
Sent 10: Why do you think this happened?
Sent 11: Where did the electricity come from?This was a discharge of static electricity.
Sent 12: Has this ever happened to you?
Sent 13: Why do you think you felt a shock?
Sent 14: What causes the electric charge to form?
Sent 15: Lightning is created in much the same way.
Sent 16: Both are caused by the build-up of electric charges.
Sent 17: This is also the same reason electric current flows through cables and wires.
Question: What are the three examples of the build-up of electric charges in this paragraph?.
Example Output:
5, 7, 8, 11, 15, 16, 17.