You are given a background paragraph that describes one or more causal or qualitative relationships such as a relationship in economics or a scientific law and a story that makes use of the concepts or the relationship described in the provided paragraph. You are also given a question about the story that requires an understanding of the relationship described in the background paragraph and the story. You need to come up with an answer to the given question; the answer will be a span from either the question or the story. In order to correctly answer the given question, you need to understand the relationship mentioned in the background paragraph and should be able to use it to understand that in the story. Your answer can not consist of any word that is not mentioned in any of these: the background paragraph, the story, or the question. You can directly copy and paste a span from the story or the question while answering the given question.

Input: Consider Input: Background Paragraph: Predators play an important role in an ecosystem. For example, if they did not exist, then a single species could become dominant over others. Grazers on a grassland keep grass from growing out of control. Predators can be keystone species . These are species that can have a large effect on the balance of organisms in an ecosystem. For example, if all of the wolves are removed from a population, then the population of deer or rabbits may increase. If there are too many deer, then they may decrease the amount of plants or grasses in the ecosystem. Decreased levels of producers may then have a detrimental effect on the whole ecosystem. In this example, the wolves would be a keystone species.
Story: Two students studied animal behavior for the biology class. Ned studied more about predators, while Kim studied more about herbivores.
Question: Which student studied less about keystone species?

Output: Kim.

Input: Consider Input: Background Paragraph: Human beings invented agriculture about 10,000 years ago. This provided a bigger, more dependable food supply. It also allowed people to settle down in villages and cities for the first time. Birth rates went up because there was more food and settled life had other advantages. Death rates also rose because of crowded living conditions and diseases that spread from domestic animals. Because the higher birth rates were matched by higher death rates, the human population continued to grow very slowly.
Story: Harry and Kim studied ancient humans. Kim studied a 15000 year-old settlement, before humans invented agriculture, while Harry studied a 5000 year-old village.
Question: Which student studied about a village that had a less dependable food supply?

Output: Kim.

Input: Consider Input: Background Paragraph: When wind waves approach to coast area from deep water, the waves change their heights and lengths. The wave height becomes higher and the wavelength becomes shorter as the wave velocity is slowed when ocean waves approach to the shore. If the water depth is sufficiently shallow, the wave crest become steeper and the trough gets broader and shallower; finally, the ocean waves break at the shore. The motions of wave breaking are different with along to the steepness of shores and waves, and can be categorized by below three types.[11][12].
Story: The tourist village had two beaches: Coral beach with nice sand and deeper water was preferred by families, and Surfer beach which had shallow water was a surfer's heaven.
Question: Which beach had fewer surfers visiting it?
Output: Coral beach.