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.

Ex Input:
Background Paragraph: Bernoulli’s law explains how the wings of both airplanes and birds create lift that allows flight (see Figure below ). The shape of the wings causes air to flow more quickly — and air pressure to be lower — above the wings than below them. This allows the wings to lift the plane or bird above the ground against the pull of gravity. A spoiler on a race car, like the one in Figure below , works in the opposite way. Its shape causes air to flow more slowly — and air pressure to be greater — above the spoiler than below it. As a result, air pressure pushes the car downward, giving its wheels better traction on the track. 
Story: Rob is experimenting with how air pressure works. To that end, he has designed two tests. In the first test the air flow works as it would in an airplane wing. He labels it as case A. In the second test the air flow works as it would in a race car spoiler. He labels it as case B. He is surprised to see that air flow behaves differently in different situations. 
Question: Would case A have higher or lower air pressure above it than case B?

Ex Output:
lower.


Ex Input:
Background Paragraph: The stronger of two acids will have a higher Ka than the weaker acid; the ratio of hydrogen ions to acid will be higher for the stronger acid as the stronger acid has a greater tendency to lose its proton. Because the range of possible values for Ka spans many orders of magnitude, a more manageable constant, pKa is more frequently used, where pKa = −log10 Ka. Stronger acids have a smaller pKa than weaker acids. Experimentally determined pKa at 25 °C in aqueous solution are often quoted in textbooks and reference material. 
Story: Jacob and Thomas were conducting an experiment in a chemistry class. The goal of the experiment was to identify the strength of unknown acids by examining the products formed in a chemical reaction. After they completed the experiment, Jacob concluded that he was given a strong acid, while Thomas concluded that he was given a weak acid. 
Question: Which person's acid, Jacob's or Thomas's, will have a larger pKa?

Ex Output:
Thomas's.


Ex Input:
Background Paragraph: Each radioactive isotope has a characteristic decay time period—the half-life—that is determined by the amount of time needed for half of a sample to decay. This is an exponential decay process that steadily decreases the proportion of the remaining isotope by 50% every half-life. Hence after two half-lives have passed only 25% of the isotope is present, and so forth. 
Story: David was working in his chemistry lab. He selected two isotopes, sample A and sample B. Sample A had longer half-life, but sample B had shorter half-life. After some time he checked sample A when its one half-life had passed. He noted it as sample A1. Then he came back to see it again when two half-lives had passed. He noted it as sample A2. 
Question: Which sample would have less isotopes, sample A or sample A1?

Ex Output:

sample A1.