Input: Read this: Thomas Edison began serious research into developing a practical incandescent lamp in 1878. Edison filed his first patent application for "Improvement In Electric Lights" on 14 October 1878. After many experiments, first with carbon in the early 1880s and then with platinum and other metals, in the end Edison returned to a carbon filament. The first successful test was on 22 October 1879, and lasted 13.5 hours. Edison continued to improve this design and by 4 November 1879, filed for a US patent for an electric lamp using "a carbon filament or strip coiled and connected ... to platina contact wires." Although the patent described several ways of creating the carbon filament including using "cotton and linen thread, wood splints, papers coiled in various ways," Edison and his team later discovered that a carbonized bamboo filament could last more than 1200 hours. In 1880, the Oregon Railroad and Navigation Company steamer, Columbia, became the first application for Edison's incandescent electric lamps (it was also the first ship to execute use of a dynamo).
Question: When did Edison begin research into incandescent lighting?

Output: 1878

Input: Read this: The five Great Lakes are located in the north-central portion of the country, four of them forming part of the border with Canada, only Lake Michigan situated entirely within United States. The southeast United States contain subtropical forests and, near the gulf coast, mangrove wetlands, especially in Florida. West of the Appalachians lies the Mississippi River basin and two large eastern tributaries, the Ohio River and the Tennessee River. The Ohio and Tennessee Valleys and the Midwest consist largely of rolling hills and productive farmland, stretching south to the Gulf Coast.
Question: Which great Lake is located entirely outside of US territory?

Output: unanswerable

Input: Read this: Admissions are characterized as "most selective" by U.S. News & World Report. There were 35,099 applications for the undergraduate class of 2020 (entering 2016), and 3,751 (10.7%) were admitted, making Northwestern one of the most selective schools in the United States. For freshmen enrolling in the class of 2019, the interquartile range (middle 50%) on the SAT was 690760 for critical reading and 710-800 for math, ACT composite scores for the middle 50% ranged from 3134, and 91% ranked in the top ten percent of their high school class.
Question: What percentage of freshman students enrolling in the class of 2009 ranked in the top 11% of their high school class?

Output: unanswerable

Input: Read this: The Duchy of Lancaster is one of two royal duchies in England. It has landholdings throughout the region and elsewhere, operating as a property company, but also exercising the right of the Crown in the County Palatine of Lancaster. While the administrative boundaries changed in the 1970s, the county palatine boundaries remain the same as the historic boundaries. As a result, the High Sheriffs for Lancashire, Greater Manchester and Merseyside are appointed "within the Duchy and County Palatine of Lancaster".
Question: Who are appointed within the Duchy and County Palatine of Lancater?

Output:
High Sheriffs