This task involves annotating the answer type to a given question that involve some kind of complex reasoning (including numerical reasoning). Note that the questions require looking at more than one part of the passage to answer. There are 3 possible answer types (i) spans, (ii) numbers and (iii) dates. If the answer can be found in the passage, label it as "span". If the answer is a number, label as "number". Similarly, label "date" if you think the answer to the given question is a date.

Input: Consider Input: Passage: Col. Edwin Sumner conducted a campaign against the Navajo in 1851. He delegated Maj. Electus Backus to build Fort Defiance in the middle of Dine bikeyah . Col Sumner entered Canyon de Chelly but Navajo harassment attacks caused him to withdraw. In 1855 a treaty was signed at Laguna Negra by Manuelito and Zarcillos Largos for the Navajo and Henry L. Dodge , Governor Merriweather, and General John Garland. Two years later a severe drought hit the Navajo and decimated their livestock and agricultural resources, causing a famine in the winter of 1857-1858. A time of social disruption ensued. Surrounding tribes gradually increased their attacks on the weakened Navajo. The Navajo demanded in 1858 that Fort Defiance stop grazing their livestock on prime Navajo land. Soldiers shot 48 cattle and 8 horses belonging to Manuelito. Navajo warriors killed a servant of the commanding officer in retaliation for the killing of their people's livestock without compensation. The United States military demanded the murderer be brought to them, or they would begin a war. The Miles Campaign was sent against them, leaving Fort Defiance on September 9.
Question: What year did a severe drought hit the Navajo?

Output: date

Input: Consider Input: Passage: The 2010 maternal mortality rate per 100,000 births for Guinea Bissau was 1000. This compares with 804.3 in 2008 and 966 in 1990. The under-5 mortality rate, per 1,000 births, was 195 and the neonatal mortality as a percentage of under-5 mortality was 24. The number of midwives per 1,000 live births was 3; one out of eighteen pregnant women die as a result of pregnancy. According to a 2013 UNICEF report, 50% of women in Guinea Bissau had undergone female genital mutilation. In 2010, Guinea Bissau had the seventh-highest maternal mortality rate in the world.
Question: Which year had the lowest maternal mortality rate?

Output: date

Input: Consider Input: Passage: The county was formed in 1752 from parts of Bladen, Granville, and Johnston Counties. It was named for the infant William V of Orange, whose mother Anne, daughter of King George II of Great Britain, was then regent of the Dutch Republic. In 1771, Orange County was greatly reduced in area. The western part of it was combined with the eastern part of Rowan County to form Guilford County. Another part was combined with parts of Cumberland County and Johnston County to form Wake County. The southern part of what remained became Chatham County. In 1777, the northern half of what was left of Orange County became Caswell County. In 1849, the western third of the still-shrinking county became Alamance County. Finally, in 1881, the eastern half of the county's remaining territory was combined with part of Wake County to form Durham County. Some of the first settlers of the county were English Quakers, who settled along the Haw and Eno Rivers. Arguably, the earliest settlers in the county were the Andrews family, which would later marry into the Lloyd family.
Question: the northern half of what was left of Orange County became Caswell County in?
Output: date