Definition: 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.
Input: Question: What other planes were fitted with the MG 15? Passage 1:As designed in 1931, the He 46 was a two-seat sesquiplane of mixed construction. The upper wing was swept back 10°. This is a common trick when a change in an aircraft's design moves the center of gravity to the rear; rather than moving the whole wing back to counter for the shift, it is easier to simply angle the wings back slightly, which requires very little change to the basic design, or even the overall structure of the wing. (The similarly angled wings on the Fairey Swordfish are due to just such a mid-program change to the weight distribution of the aircraft.) The tailplane was mounted high and braced by struts. The undercarriage was fixed, and the tail was fitted with a skid rather than a wheel. The He 46 prototype first flew in late 1931; its flight characteristics were good, but design improvements were incorporated. The small lower wing was removed, while the mainplane was increased in area by 22% and braced to the fuselage, transforming the He 46 into a parasol-wing monoplane. A more powerful engine was added to the second prototype, and a single 7.92 mm (.312 in) MG 15 machine gun for the rear seat was added to the third prototype.
 Passage 2:On 7 October 1593, the superintendent of the Venetian Republic founded a revolutionary new kind of settlement: Palmanova. The city’s founding date commemorated the victory of the Christian forces (supplied primarily by the Italian states and the Spanish kingdom) over the Ottoman Turks in the Battle of Lepanto in 1571, during the War of Cyprus. Also honored on 7 October was Saint Justina, chosen as the city's patron saint. Using all the latest military innovations of the 16th century, this small town was a fortress in the shape of a nine-pointed star, designed by Vincenzo Scamozzi. Between the points of the star, ramparts protruded so that the points could defend each other. A moat surrounded the town, and three large, guarded gates allowed entry. The construction of the first circle, with a total circumference of , took 30 years. Marcantonio Barbaro headed a group of Venetian noblemen in charge of building the town, Marcantonio Martinego was in charge of construction, and Giulio Savorgnan acted as an adviser. A second phase of construction took place between 1658 and 1690, and the outer line of fortifications was completed between 1806 and 1813 under the Napoleonic domination. The final fortress consists of: 9 ravelins, 9 bastions, 9 lunettes, and 18 cavaliers.
 Passage 3:On 16 June 2009, The Black Eyed Peas released the Guetta-produced "I Gotta Feeling" as their second single from their fifth studio album, The E.N.D.. It became a worldwide hit topping the charts in seventeen countries. It became the most downloaded song of all-time in the United States with almost 7.5 million downloads and in the United Kingdom selling more than 1 million copies. He was nominated twice for his work with The Black Eyed Peas at the 52nd Grammy Awards; in the category Record of the Year for "I Gotta Feeling" and Album of the Year for their album The E.N.D.. In 2010, Guetta co-wrote and produced Kelly Rowland's "Commander" from her third album Here I Am. It peaked at number one on Billboard's Hot Dance Club Songs chart in the United States, and reached top ten positions in Belgium and the United Kingdom. Guetta has also co-produced "Forever and a Day", which was Kelly's next UK single from that album. Guetta also produced the singles "Acapella" and "Scream" for American singer-songwriter Kelis's fifth studio album, Flesh Tone, released on 14 May 2010. "Acapella" was released as the lead single on 23 February 2010 and topped the dance charts in the United Kingdom and United States. On 28 June 2010 American rapper Flo Rida released the single "Club Can't Handle Me" featuring Guetta. The song is included on the soundtrack album to the American 3D dance film Step Up 3D and Flo Rida's third studio album, Only One Flo (Part 1).

Output:
1