In this task, you will be presented with a context passage, a question about that paragraph, and a possible answer to that question. The task is to check the validity of the answer. Answer with "Yes" or "No".

Ex Input:
Alexander II (Russian: Aleksandr II Nikolaevich, tr. Aleksandr II Nikolaevich; IPA: [aljI'ksandr fta'roj njIka'lajIvjItc]; 29 April [O.S. 17 April] 1818 in Moscow - 13 March [O.S. 1 March] 1881 in Saint Petersburg) was the Emperor of Russia from 2 March 1855 until his assassination in 1881. He was also the King of Poland and the Grand Duke of Finland. Alexander was the most successful Russian reformer since Peter the Great. His most important achievement was the emancipation of serfs in 1861, for which he became known as Alexander the Liberator (Russian: Aleksandr Osvoboditel', tr. Aleksandr Osvoboditel; IPA: [aljI'ksandr asv@ba'djitjIlj]). The tsar was responsible for numerous other reforms including reorganizing the judicial system, setting up elected local judges, abolishing capital punishment, promoting local self-government through the zemstvo system, imposing universal military service, ending some of the privileges of the nobility, and promoting the universities. Despite these reforms, during his reign, his brutal secret police, known as the Third Section, sent thousands of dissidents into exile in Siberia. In foreign policy, Alexander sold Alaska to the United States in 1867, fearing the remote colony would fall into British hands if there was another war. He sought peace, moved away from bellicose France when Napoleon III fell in 1871, and in 1872 joined with Germany and Austria in the League of the Three Emperors that stabilized the European situation. Despite his otherwise pacifistic foreign policy, he fought a brief war with Turkey in 1877-78, pursued further expansion into Siberia and the Caucasus, and conquered Turkestan. Although disappointed by the results of the Congress of Berlin in 1878, Alexander abided by that agreement. Among his greatest domestic challenges was an uprising in Poland in 1863, to which he responded by stripping that land of its separate Constitution and incorporating it directly into Russia. Alexander was proposing additional parliamentary reforms to counter the rise of nascent revolutionary and anarchistic movements when he was assassinated in 1881. <sep>Why is Alexander II called Aleksandr Osvoboditel?<sep>For his emancipation of serfs

Ex Output:
Yes

Ex Input:
Have you ever looked closely at a globe? That continents look like a giant jig-saw puzzle. North America looks like it could fit next to Europe. The edge of South America matches Africa. Scientists noticed these same features. It caused them to start asking questions. They wanted to know if these continents were was connected? If so, how can something so large move so far? What could possibly have enough force to move such a giant slab of rock? Is there other evidence that can provide clues to the past positions of continents? How can answering these questions help us? A scientist named Alfred Wegener had these same questions. Wegener look at rocks on both sides of the Atlantic Ocean. He noticed they were the same type and age. He thought that the rocks must have formed side by side. He proposed that the rocks then drifted apart. One part went with North America. The other part stayed with Europe. <sep>What features did the scientists notice<sep>That the continents look like a giant jig-saw puzzle

Ex Output:
Yes

Ex Input:
The inhabited history of the Las Vegas Valley stretches to 23,000 b.c. , when much of the area was covered by a prehistoric lake. During this period, the indigenous people lived in caves, hunting the mammals that gathered at the shoreline. The landscape of the valley changed dramatically over the next 200 centuries. The glaciers feeding the lake melted away and the lake evaporated. Fossils tell an obscure story of man's slow and sporadic development. Around 3000 b.c. , native Archaic Indians began to develop a lasting hunting and gathering culture. By this time, the valley was in much the same geographic state as it exists in today, with one exceptionthe presence of artesian springs that bubbled to the surface in several areas. These springs fed a network of streams draining through the Las Vegas Wash to the Colorado River. The areas surrounding the springs were desert oases: sprawling collections of grasses, trees, and wildlife. Many springs lay in areas that would eventually become the center of the modern Las Vegas metropolis. For about 4000 years, the Archaics thrived in a culture that included many signs of early civilization. Signs of even more advancement appeared halfway through the first millennium a.d. , when the Anasazi Indians inhabited the valley. Far more progressive than the Archaics, the Anasazi utilized such formal agricultural techniques as irrigation to assist their harvest. This permitted the Anasazi to achieve a benchmark of advanced societythe ability to live in permanent shelters year-round without need to follow wildlife. Mysteriously, the Anasazi vanished from the valley around a.d. <sep>What was the geographic state of Las Vegas in 3000 BC and what rivers did the streams feed?<sep>A prehistoric lake, Las Vegas Valley

Ex Output:
No