Detailed Instructions: 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 (", ").
Q: Paragraph- Sent 1: Littlefoot 's grandfather one night tells the children a story about `` The Lone Dinosaur '' , a legendary longneck who once protected the Great Valley from the most ferocious sharptooth ever to live .
Sent 2: A fight ensued , which led to the Sharptooth 's death .
Sent 3: However , the sharptooth left `` The Lone Dinosaur '' with a scar slashed across his right eye .
Sent 4: Soon after the battle , a huge monolith that resembled a proud sauropod , having life-sized Sharptooth teeth arranged around his neck , came out of the ground during an earthquake .
Sent 5: The dinosaurs called it `` Saurus Rock '' .
Sent 6: The legend also states that if anyone damages the monolith , bad luck would descend upon the valley .
Sent 7: A few days later when the kids are playing , Littlefoot accidentally falls off a cliff .
Sent 8: Just before he hits the ground , a gruff Diplodocus rescues him .
Sent 9: This longneck introduces himself only as `` Doc '' and gives no knowledge of his history .
Sent 10: Littlefoot is intrigued by this newcomer , who is scarred across one eye and displays prior knowledge of the Great Valley 's topography .
Sent 11: For the preceding reasons , Littlefoot assumes that Doc is the Lone Dinosaur .
Sent 12: He tells his friends this , narrating an apparently extemporaneous legend to support his assumption .
Sent 13: Inspired , Cera 's infant nieces , the twins Dinah and Dana , go to Saurus Rock without anyone noticing .
Sent 14: Later when the friends are playing , they notice that Dinah and Dana are missing .
Sent 15: Recalling their talk of the day before , they go to Saurus Rock to find them . 
Question: Who goes missing at the end of the story?.
A:
13, 14.