Input: Read this: While Southeast Asia is rich in flora and fauna, Southeast Asia is facing severe deforestation which causes habitat loss for various endangered species such as orangutan and the Sumatran tiger. Predictions have been made that more than 40% of the animal and plant species in Southeast Asia could be wiped out in the 21st century. At the same time, haze has been a regular occurrence. The two worst regional hazes were in 1997 and 2006 in which multiple countries were covered with thick haze, mostly caused by "slash and burn" activities in Sumatra and Borneo. In reaction, several countries in Southeast Asia signed the ASEAN Agreement on Transboundary Haze Pollution to combat haze pollution.
Question: What caused the 19th century reginal hazes?

Output: unanswerable


Input: Read this: The modern Standard Chinese exonym for the ethnic Tibetan region is Zangqu (Chinese: 藏区; pinyin: Zàngqū), which derives by metonymy from the Tsang region around Shigatse plus the addition of a Chinese suffix, 区 qū, which means "area, district, region, ward". Tibetan people, language, and culture, regardless of where they are from, are referred to as Zang (Chinese: 藏; pinyin: Zàng) although the geographical term Xīzàng is often limited to the Tibet Autonomous Region. The term Xīzàng was coined during the Qing dynasty in the reign of the Jiaqing Emperor (1796–1820) through the addition of a prefix meaning "west" (西 xī) to Zang.
Question: What is the Tsang exonym for the ethnic Tibetan region?

Output: unanswerable


Input: Read this: Software developers can't test everything, but they can use combinatorial test design to identify the minimum number of tests needed to get the coverage they want. Combinatorial test design enables users to get greater test coverage with fewer tests. Whether they are looking for speed or test depth, they can use combinatorial test design methods to build structured variation into their test cases. Note that "coverage", as used here, is referring to combinatorial coverage, not requirements coverage.
Question: Combinatorial test design does not allow users to get what?

Output: unanswerable


Input: Read this: The first record of the existence of a settlement at Plymouth was in the Domesday Book in 1086 as Sudtone, Saxon for south farm, located at the present day Barbican. From Saxon times, it was in the hundred of Roborough. In 1254 it gained status as a town and in 1439, became the first town in England to be granted a Charter by Parliament. Between 1439 and 1934, Plymouth had a Mayor. In 1914 the county boroughs of Plymouth and Devonport, and the urban district of East Stonehouse merged to form a single county borough of Plymouth. Collectively they were referred to as "The Three Towns".
Question: In what year did Parliament bestow a Charter on Plymouth?

Output:
1439