Question: Who was the 2017 leader of the country first to sell hamburgers outside the US?

full_context: Document 1: Big Mac: The Big Mac is a hamburger sold by international fast food restaurant chain McDonald's. It was introduced in the Greater Pittsburgh area, United States, in 1967 and nationwide in 1968. It is one of the company's signature products.
Document 2: Prime Minister of the United Kingdom: The Prime Minister of the United Kingdom is the head of Her Majesty's Government in the United Kingdom. The Prime Minister (informally abbreviated to PM) and Cabinet (consisting of all the most senior ministers, most of whom are government department heads) are collectively accountable for their policies and actions to the Monarch, to Parliament, to their political party and ultimately to the electorate. The office is one of the Great Offices of State. The current holder of the office, Theresa May, leader of the Conservative Party, was appointed by the Queen on 13 July 2016.
Document 3: History of the hamburger: The modern hamburger was developed in the United States, but by the end of World War II, around the middle of the 20th century, it began to spread to other countries as fast food became globalized. The main cause of this gradual globalization was the successes of the large restaurant chains. Their desires to expand their businesses and increase their profits resulted in them creating franchises around the world. McDonald's was among the very first of the burger chains to take the global establishment of its brand seriously, but it was not the only one. Wimpy began operating in the United Kingdom in 1954, 20 years before McDonald's began operation in the country, and by 1970 it had expanded to over a thousand restaurants in 23 countries. On August 21, 1971, in Zaandam, near Amsterdam in the Netherlands, Ahold opened its first European franchise. In the 1970s, McDonald's began to expand into Europe and Australia. In Asia, Japan saw the establishment of its own fast food chain in 1972: MOS Burger (モスバーガー, Mosu bāgā), an abbreviation of ``Mountain, Ocean, Sun '', which eventually became a direct competitor to McDonald's. All of its products, however, were variations on the burger adapted to the Asian world, including the teriyaki burger, takumi burger, and riceburger. In Hong Kong, Aji Ichiban competed with large chains before it spread quickly throughout Asia. One of the first hamburger vending machines debuted in Amsterdam in 1941 under the brand FEBO, its name derived from its original place of creation, the Ferdinand Bolstraat.
Document 4: Government of Canada: The monarch (presently Queen Elizabeth II) is personally represented by the Governor General of Canada (currently Julie Payette). The Queen's Privy Council for Canada is the body that advises the sovereign or viceroy on the exercise of executive power. However, in practice, that task is performed only by the Cabinet, a committee within the Privy Council composed of ministers of the Crown, who are drawn from and responsible to the elected House of Commons in parliament. The Cabinet is headed by the prime minister (presently Justin Trudeau), who is appointed by the governor general after securing the confidence of the House of Commons.
Document 5: Parliament of the United Kingdom: The House of Commons is a democratically elected chamber with elections held at least every five years. The two Houses meet in separate chambers in the Palace of Westminster (commonly known as the Houses of Parliament) in London. By constitutional convention, all government ministers, including the Prime Minister, are members of the House of Commons or, less commonly, the House of Lords and are thereby accountable to the respective branches of the legislature. Most cabinet ministers (Secretaries of State) are from the Commons, whilst junior ministers can be from either House. However, it should be noted the Leader of the House of Lords must be a peer and is a cabinet position, usually combined with a paid position.
Document 6: Prime Minister of the United Kingdom: Prime Minister of the United Kingdom of Great Britain and Northern Ireland Royal Arms used by Her Majesty's Government Incumbent Theresa May since 13 July 2016 (2016 - 07 - 13) Government of the United Kingdom Office of the Prime Minister Style Prime Minister (informal) The Right Honourable (within the UK and the Commonwealth) His / Her Excellency (in international correspondence) Member of Cabinet Privy Council European Council British -- Irish Council Reports to Parliament Residence 10 Downing Street Chequers Seat Westminster Appointer Monarch of the United Kingdom Term length At Her Majesty's pleasure Inaugural holder Sir Robert Walpole as First Lord of the Treasury and de facto first Prime Minister. Formation 4 April 1721 Salary £151,451 annual, including £76,011 MP's salary Website Official website
Document 7: Government of the United Kingdom: The current prime minister is Theresa May, who took office on 13 July 2016. She is the leader of the Conservative Party, which won a majority of seats in the House of Commons in the general election on 7 May 2015, when David Cameron was the party leader; although at the last general election she failed to secure a majority government. Prior to this, Cameron and the Conservatives led a coalition from 2010 to 2015 with the Liberal Democrats, in which Cameron was prime minister.
Document 8: Big Mac: The Big Mac is a hamburger sold by international fast food restaurant chain McDonald's. It was introduced in the Greater Pittsburgh area, United States, in 1967 and nationwide in 1968. It is one of the company's flagship products.
Document 9: Fried pie: Fast food versions have gained popularity more recently. McDonald's apple pies were introduced on the menu in 1968, but in 1992 they were phased out in favor of a baked pie (claimed to be healthier) in the United States. There are some McDonald's restaurants throughout the US and world which still offer the fried pies, including all McDonald's restaurants in the United Kingdom, Japan, and Russia. Flavors include cherry and apple (US mainland), taro (Hawaii), and green bean or red bean (China). The Burger King chain also offers fried pies on its menu, in apple and ``wild berry ''flavors. Whataburger and Popeyes also offer fried pies.
Document 10: Fast food restaurant: Some historians concur that A&W, which opened in 1919 and began franchising in 1921, was the first fast food restaurant (E. Tavares). Thus, the American company White Castle is generally credited with opening the second fast - food outlet in Wichita, Kansas in 1921, selling hamburgers for five cents apiece from its inception and spawning numerous competitors and emulators. What is certain, however, is that White Castle made the first significant effort to standardize the food production in, look of, and operation of fast - food hamburger restaurants. William Ingram's and Walter Anderson's White Castle System created the first fast food supply chain to provide meat, buns, paper goods, and other supplies to their restaurants, pioneered the concept of the multi-state hamburger restaurant chain, standardized the look and construction of the restaurants themselves, and even developed a construction division that manufactured and built the chain's prefabricated restaurant buildings. The McDonald's Speedee Service System and, much later, Ray Kroc's McDonald's outlets and Hamburger University all built on principles, systems and practices that White Castle had already established between 1923 and 1932.
Document 11: Oldest McDonald's restaurant: The McDonald brothers opened their first restaurant adjacent to the Monrovia Airport in 1937. It was a tiny octagonal building informally called The Airdrome. That octagonal building was later moved to 1398 North E Street in San Bernardino, California, in 1940. It was originally a barbecue drive - in, but the brothers discovered that most of their profits came from hamburgers. In 1948, they closed their restaurant for three months, reopening it in December as a walk - up hamburger stand that sold hamburgers, potato chips, and orange juice; the following year, french fries and Coca - Cola were added to the menu. This simplified menu, and food preparation using assembly line principles, allowed them to sell hamburgers for 15 cents, or about half as much as at a sit - down restaurant. The restaurant was very successful, and the brothers started to franchise the concept in 1953.
Document 12: Leader of the Conservative Party (UK): Leader of the Conservative Party Incumbent Theresa May since 11 July 2016 Inaugural holder Robert Peel (de facto) Bonar Law (de jure) Formation 1834 (de facto) 1922 (de jure)
Document 13: Fast food restaurant: Some historians concur that A&W, which opened in 1921 and began franchising in 1923, was the first fast food restaurant (E. Tavares). Thus, the American company White Castle is sometimes considered the second fast - food outlet in Wichita, Kansas in 1921, selling hamburgers for five cents apiece from its inception and spawning numerous competitors and emulators. What is certain, however, is that White Castle made the first significant effort to standardize the food production in, look of, and operation of fast - food hamburger restaurants. William Ingram's and Walter Anderson's White Castle System created the first fast food supply chain to provide meat, buns, paper goods, and other supplies to their restaurants, pioneered the concept of the multi-state hamburger restaurant chain, standardized the look and construction of the restaurants themselves, and even developed a construction division that manufactured and built the chain's prefabricated restaurant buildings. The McDonald's Speedee Service System and, much later, Ray Kroc's McDonald's outlets and Hamburger University all built on principles, systems and practices that White Castle had already established between 1923 and 1932.
Document 14: McDonald's: McDonald's is an American fast food company, founded in 1940 as a restaurant operated by Richard and Maurice McDonald, in San Bernardino, California, United States. They rechristened their business as a hamburger stand. The first time a McDonald's franchise used the Golden Arches logo was in 1953 at a location in Phoenix, Arizona. In 1955, Ray Kroc, a businessman, joined the company as a franchise agent and proceeded to purchase the chain from the McDonald brothers. McDonald's had its original headquarters in Oak Brook, Illinois, but moved its global headquarters to Chicago in early 2018.
Document 15: Prime Minister of India: The union cabinet headed by the prime minister is appointed by the President of India to assist the latter in the administration of the affairs of the executive. Union cabinet is collectively responsible to the Lok Sabha as per article 75 (3) of the Constitution of India. The prime minister has to enjoy the confidence of a majority in the Lok Sabha and shall resign if they are unable to prove majority when instructed by the president.
ground_truth: Theresa May
sub_queries: where did the hamburger make its international debut Answer: the United Kingdom
who is the leader of the United Kingdom 2017 Answer: Theresa May