Input: Article: The earliest known cultural tribes of the area were members of the Hallstatt and La Tène cultures, named after the archaeological site of La Tène on the north side of Lake Neuchâtel. La Tène culture developed and flourished during the late Iron Age from around 450 BC, possibly under some influence from the Greek and Etruscan civilisations. One of the most important tribal groups in the Swiss region was the Helvetii. Steadily harassed by the Germans, in 58 BC the Helvetii decided to abandon the Swiss plateau and migrate to western Gallia, but Julius Caesar's armies pursued and defeated them at the Battle of Bibracte, in today's western France, forcing the tribe to move back to its original homeland. In 15 BC, Tiberius, who was destined to be the second Roman emperor and his brother, Drusus, conquered the Alps, integrating them into the Roman Empire. The area occupied by the Helvetii—the namesakes of the later Confoederatio Helvetica—first became part of Rome's Gallia Belgica province and then of its Germania Superior province, while the eastern portion of modern Switzerland was integrated into the Roman province of Raetia. Sometime around the start of the Common Era, the Romans maintained a large legionary camp called Vindonissa, now a ruin at the confluence of the Aare and Reuss rivers, near the town of Windisch, an outskirt of Brugg.

Now answer this question: In what year did Tiberius conquer the Alps, integrating them into the Roman Empire?

Output: 15 BC

Input: Article: The iTunes Store (introduced April 29, 2003) is an online media store run by Apple and accessed through iTunes. The store became the market leader soon after its launch and Apple announced the sale of videos through the store on October 12, 2005. Full-length movies became available on September 12, 2006.

Now answer this question: In what year did videos first become available on iTunes?

Output: 2005

Input: Article: Addition of lead(II) oxide lowers melting point, lowers viscosity of the melt, and increases refractive index. Lead oxide also facilitates solubility of other metal oxides and is used in colored glasses. The viscosity decrease of lead glass melt is very significant (roughly 100 times in comparison with soda glasses); this allows easier removal of bubbles and working at lower temperatures, hence its frequent use as an additive in vitreous enamels and glass solders. The high ionic radius of the Pb2+ ion renders it highly immobile in the matrix and hinders the movement of other ions; lead glasses therefore have high electrical resistance, about two orders of magnitude higher than soda-lime glass (108.5 vs 106.5 Ohm·cm, DC at 250 °C). For more details, see lead glass.

Now answer this question: What makes glass melt at a lower temperature?

Output:
lead(II) oxide