In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

Ex Input:
Waves contain?, Context: As an electro-magnetic wave travels through the different parts of the antenna system (radio, feed line, antenna, free space) it may encounter differences in impedance (E/H, V/I, etc.). At each interface, depending on the impedance match, some fraction of the wave's energy will reflect back to the source, forming a standing wave in the feed line. The ratio of maximum power to minimum power in the wave can be measured and is called the standing wave ratio (SWR). A SWR of 1:1 is ideal. A SWR of 1.5:1 is considered to be marginally acceptable in low power applications where power loss is more critical, although an SWR as high as 6:1 may still be usable with the right equipment. Minimizing impedance differences at each interface (impedance matching) will reduce SWR and maximize power transfer through each part of the antenna system.

Ex Output:
power


Ex Input:
which is not a last name, Kroc or Branch?, Context: The library system also includes branch libraries for Architecture, Chemistry & Physics, Engineering, Law, and Mathematics as well as information centers in the Mendoza College of Business, the Kellogg Institute for International Studies, the Joan B. Kroc Institute for International Peace Studies, and a slide library in O'Shaughnessy Hall. A theology library was also opened in fall of 2015. Located on the first floor of Stanford Hall, it is the first branch of the library system to be housed in a dorm room. The library system holds over three million volumes, was the single largest university library in the world upon its completion, and remains one of the 100 largest libraries in the country.

Ex Output:
branch


Ex Input:
What happened about 355 years after Thuringia became a landgraviate?, Context: Thuringia became a landgraviate in 1130 AD. After the extinction of the reigning Ludowingian line of counts and landgraves in 1247 and the War of the Thuringian Succession (1247–1264), the western half became independent under the name of "Hesse", never to become a part of Thuringia again. Most of the remaining Thuringia came under the rule of the Wettin dynasty of the nearby Margraviate of Meissen, the nucleus of the later Electorate and Kingdom of Saxony. With the division of the house of Wettin in 1485, Thuringia went to the senior Ernestine branch of the family, which subsequently subdivided the area into a number of smaller states, according to the Saxon tradition of dividing inheritance amongst male heirs. These were the "Saxon duchies", consisting, among others, of the states of Saxe-Weimar, Saxe-Eisenach, Saxe-Jena, Saxe-Meiningen, Saxe-Altenburg, Saxe-Coburg, and Saxe-Gotha; Thuringia became merely a geographical concept.

Ex Output:

the division of the house of Wettin