In this task, you're given a question, along with three passages, 1, 2, and 3. Your job is to determine which passage can be used to answer the question by searching for further information using terms from the passage. Indicate your choice as 1, 2, or 3.

Example input: Question: When did the operation during which the 704th dropped supplies to allied troops near Nijmegen begin? Passage 1: The group was occasionally diverted from strategic missions to carry out air support and interdiction missions. It supported Operation Overlord, the invasion of Normandy by attacking transportation targets, including bridges, along with airfields and strong points in France. On D Day, the squadron and the rest of the 446th Group led the first heavy bomber mission of the day. The 446th aided ground forces at Caen and Saint-Lô during July by hitting bridges, gun batteries, and enemy troops. During Operation Market Garden, the attempt to seize a bridgehead across the Rhine in the Netherlands, the 704th dropped supplies to allied troops near Nijmegen. It struck lines of communications during the Battle of the Bulge. During Operation Varsity in March 1945, it supplied ground and airborne troops near Wesel. The squadron flew its last combat mission on 25 April 1945 against Salzburg, Austria. The group had flown 273 missions and had lost 58 aircraft during the war,
. Passage 2: John Ford (1894–1973) was an American film director whose career spanned from 1913 to 1971. During this time he directed more than 140 films. Born in Maine, Ford entered the filmmaking industry shortly after graduating from high school with the help of his older brother, Francis Ford, who had established himself as a leading man and director for Universal Studios. After working as an actor, assistant director, stuntman, and prop man – often for his brother – Universal gave Ford the opportunity to direct in 1917. Initially working in short films, he quickly moved into features, largely with Harry Carey as his star. In 1920 Ford left Universal and began working for the Fox Film Corporation. During the next ten years he directed more than 30 films, including the westerns The Iron Horse (1924) and 3 Bad Men (1926), both starring George O'Brien, the war drama Four Sons and the Irish romantic drama Hangman's House (both 1928 and both starring Victor McLaglen). In the same year of these last two films, Ford directed his first all-talking film, the short Napoleon's Barber. The following year he directed his first all-talking feature, The Black Watch.
. Passage 3: Since the late 1970s, the central part of NYU is its Washington Square campus in the heart of Greenwich Village. Despite being public property, and expanding the Fifth Avenue axis into Washington Square Park, the Washington Square Arch is the unofficial symbol of NYU. Until 2008, NYU's commencement ceremony was held in Washington Square Park. However, due to space constraints, ceremonies are now held at the Yankee Stadium. Important facilities at Washington Square are the Elmer Holmes Bobst Library, designed by Philip Johnson and Richard Foster, who also designed several other structures, such as Tisch Hall, Meyer Hall, and the Hagop Kevorkian Center. When designing these buildings Johnson and Foster also set up a master plan for a complete redesign of the NYU Washington Square campus. However, it was never implemented. Other historic buildings include the Silver Center (formerly known as "Main building"); the Brown Building of Science; Judson Hall, which houses the King Juan Carlos I of Spain Center; Vanderbilt Hall, the historic townhouse row on Washington Square North; The Grey Art Gallery at 100 Washington Square East, housing the New York University art collection and featuring museum quality exhibitions; the Kaufman Management Center; and the Torch Club – the NYU dining and club facility for alumni, faculty, and administrators. Just a block south of Washington Square is NYU's Washington Square Village, housing graduate students and junior and senior faculty residences in the Silver Towers, designed by I. M. Pei, where an enlargement of Picasso's sculpture Bust of Sylvette (1934) is displayed.
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Example output: 1
Example explanation: The question refers to the 704th unit and task about war which is decribed by Passage 1.
Q: Question: How old was Alikhanov when Pomeranchuk studied with him? Passage 1:McCammon never played in the NHL, spending his entire career in the minor leagues. He was the head coach of the Maine Mariners of the American Hockey League and won the Calder Cup in 1977-78 and 1978–79, the first two years of the team's existence. McCammon had two stints as head coach of the Philadelphia Flyers, also serving as the team's general manager during the latter. He was also the head coach of the Vancouver Canucks and an assistant coach for the Edmonton Oilers on two different occasions. With Vancouver in 1988–89, he was runner-up to Pat Burns of the Montreal Canadiens for the Jack Adams Trophy as NHL Coach of the Year. He won the Stanley Cup with the Edmonton Oilers in 1987 as director of player development, and in 2002 and 2008 as a scout with Detroit. McCammon's name was added to the Stanley Cup in 2002 with Detroit. 
 Passage 2:After Landau moved to the Kapitza institute in Moscow (to avoid arrest for comparing Stalinism to Nazism), Pomeranchuk also moved there, working for the tanning industry. He returned to Leningrad in 1938, lecturing, completing his Ph.D. and becoming employed as a junior scientist. He joined the Lebedev Institute of the Academy of Sciences of the USSR in Moscow as a senior scientist in 1940. In 1941 the institute was evacuated to Kazan. Under Abraham Alikhanov, he studied cosmic rays in Armenia from 1942. In 1943, he transferred to Laboratory No.2 under Igor Kurchatov as part of the Soviet project to develop nuclear weapons. Alikhanov founded Laboratory No.3 (which became the Institute for Theoretical and Experimental Physics (ITEP)) and Pomeranchuk worked there from 1946 (and for the rest of his life), founding and leading the Theoretical department, as well as being Professor of Theoretical Physics at the Moscow Mechanical Institute where students admired his infectious enthusiasm for his subject. Rudolf Peierls was consoled by the fact that it was "very clever Pomeranchuk" - and no-one else - who corrected his 1/T law for heat conduction in high-temperature condensed matter physics. His work in the 1940s was dominated by neutron research and his manuscript with Akhiezer was the basic guide for Soviet nuclear reactor construction. In 1950, he published a paper suggesting that the entropy of helium-3 as a liquid was less than as a solid. In 1950, Pomeranchuk received an order from Josef Stalin to go to Arzamas-16, located in the closed city of Sarov, Nizhny Novgorod region, to work on Soviet nuclear weaponry. Missing his family and his 'hobby physics' problems, he was advised not to apply for a revocation but wait until the order was "forgotten." He returned to ITEP within a year. He continued enthusiastically with work on quantum field theory and S-matrix theory, particle collisions and Regge theory, the latter in vigorous collaboration with Vladimir Gribov. His last paper on Regge theory was published posthumously. For his work, Pomeranchuk was twice awarded the Stalin Prize (1950, 1952). He was elected a corresponding member of the Academy of Sciences of the USSR in 1953 and full member in 1964.
 Passage 3:After playing junior hockey for the Sioux Falls Stampede of the United States Hockey League (USHL), Vanek joined the University of Minnesota Golden Gophers, leading the team in goals (31), assists (31) and points (62) in the 2002–03 season. In part due to his prolific scoring touch, the Golden Gophers won the 2003 NCAA National Championship. Vanek was named MVP of the Frozen Four tournament, scoring the game-winning goals in both the semifinal against Michigan in overtime and in the final against New Hampshire. He was also named Minnesota's team MVP for 2003, becoming the first freshman to receive the honor. He scored the most points by a Golden Gopher freshman in 2003 since Aaron Broten who scored 72 total points in 1979–80. He was the first freshman to lead the team in scoring since Mike Antonovich in 1969–70. His 31 goals also led all NCAA freshmen in goal scoring, and was fourth in the entire country. He was also the 2003 WCHA Rookie of the Year, the third Golden Gopher to win the award.

A:
2