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: Air pollution is harmful to human beings and other living things. About 22 million people die from air pollution each year. Breathing polluted air increases the risk of developing lung diseases such as asthma and lung cancer. Breathing bad air also increases the chances of dying from other diseases. Children are most likely to be affected by air pollution. That’s because their lungs are still developing and growing. Children also take in more air for their size than adults do. Some air pollutants damage the environment as well as the health of living things. The type of damage depends on the pollutant. Air pollution can also harm the environment. 
Story: Two sister cities were part of an air pollution study. While Prague had big air pollution problems, Belfast was eco-friendly and its inhabitants were healthy. 
Question: Which city had fewer people with an increased chance of developing lung disease?

Output: Belfast.


Input: Consider Input: Background Paragraph: The Human Immunodeficiency Virus ( HIV ) is the virus that causes Acquired Immunodeficiency Syndrome ( AIDS ). Most researchers believe that the HIV originated in sub-Saharan Africa during the 20th century. HIV is transmitted by sexual contact and by contact with infected bodily fluids, such as blood, semen, breast milk, and vaginal secretions. It is also passed from mother to fetus. HIV is now a pandemic , with an estimated (as of 2008) 38.6 million people now living with the disease worldwide. It is estimated that AIDS has killed more than 25 million people since it was first recognized in 1981. 
Story: Dean and Paul both went to volunteered in Africa. They had a blood test when they came back. Paul had been infected with the HIV virus while Dean was healthy and clean. 
Question: Which friend has a virus that is transmitted by contact with infected semen?

Output: Paul.


Input: Consider Input: Background Paragraph: An allergy is a disease in which the immune system makes an inflammatory response to a harmless antigen . Any antigen that causes an allergy is called an allergen. Allergens may be inhaled or ingested, or they may come into contact with the skin. Two common causes of allergies are shown in Figure below . Inhaling ragweed pollen may cause coughing and sneezing. Skin contact with oils in poison ivy may cause an itchy rash. Other common causes of allergies include dust mites, mold, animal dander, insect stings, latex, and certain food and medications. Symptoms of a common allergy such as pollen can include sneezing, a runny nose, nasal congestion and itchy, watery eyes. 
Story: A pharmaceutical company is trying to find the cure for allergy. To that end, they conducted an experiment with two groups of subjects, group A and group B. They exposed the participants in group A to allergen, but they didn't expose the participants in group B to any allergen. The symptoms of these two groups would help them find the cure for allergy. 
Question: Which group would not get itchy rash, group A or group B?


Output: group B.