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: Which of the two rivers the Panzer Corps crossed was larger? 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:In planning for the actual attack, Manteuffel had divided his 5th Panzer Army into three corps composed of infantry, tanks, and supporting artillery. The main effort, or schwerpunkt, would consist of XLVII Panzer Corps and LVIII Panzer Corps advancing west across the River Our at Ouren from the south or left flank of the German army front. They would then occupy the transportation center of Bastogne, before crossing the Meuse River at Namur. The third group, LXVI Corps, would advance west on either side of the Schnee Eifel. This northernmost, or right wing, element would flank and begin an envelopment of the American forces occupying fortifications on the Schnee Eifel and then converge on the town of Winterspelt. From there, LXVI Corps would cross the Our river and occupy St. Vith on the first day of the attack. LXVI Corps was the weakest of the three corps, with no attached tank division or motor transport, but did include an attached assault gun battalion. The Panzer Lehr Division (Armor Demonstration Division) and the Führer Begleit Brigade (Führer Escort Brigade) were to be held in reserve, with the Führer Begleit only usable with Model's express permission. Manteuffel's preference for the "little slam", or limited solution, was reflected in the absence of planning beyond reaching the Meuse River.
 Passage 3: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.

Output:
2