Input: Read this: The ultimate substantive legacy of Principia Mathematica is mixed. It is generally accepted that Kurt Gödel's incompleteness theorem of 1931 definitively demonstrated that for any set of axioms and inference rules proposed to encapsulate mathematics, there would in fact be some truths of mathematics which could not be deduced from them, and hence that Principia Mathematica could never achieve its aims. However, Gödel could not have come to this conclusion without Whitehead and Russell's book. In this way, Principia Mathematica's legacy might be described as its key role in disproving the possibility of achieving its own stated goals. But beyond this somewhat ironic legacy, the book popularized modern mathematical logic and drew important connections between logic, epistemology, and metaphysics.
Question: Godel couldn't have come to his conclusion without what book?

Output: Principia Mathematica


Input: Read this: In London Chopin took lodgings at Dover Street, where the firm of Broadwood provided him with a grand piano. At his first engagement, on 15 May at Stafford House, the audience included Queen Victoria and Prince Albert. The Prince, who was himself a talented musician, moved close to the keyboard to view Chopin's technique. Broadwood also arranged concerts for him; among those attending were Thackeray and the singer Jenny Lind. Chopin was also sought after for piano lessons, for which he charged the high fee of one guinea (£1.05 in present British currency) per hour, and for private recitals for which the fee was 20 guineas. At a concert on 7 July he shared the platform with Viardot, who sang arrangements of some of his mazurkas to Spanish texts.
Question: Where was Chopin's initial performance?

Output: Stafford House


Input: Read this: In Singapore, madrasahs are private schools which are overseen by Majlis Ugama Islam Singapura (MUIS, English: Islamic Religious Council of Singapore). There are six Madrasahs in Singapore, catering to students from Primary 1 to Secondary 4. Four Madrasahs are coeducational and two are for girls. Students take a range of Islamic Studies subjects in addition to mainstream MOE curriculum subjects and sit for the PSLE and GCE 'O' Levels like their peers. In 2009, MUIS introduced the "Joint Madrasah System" (JMS), a joint collaboration of Madrasah Al-Irsyad Al-Islamiah primary school and secondary schools Madrasah Aljunied Al-Islamiah (offering the ukhrawi, or religious stream) and Madrasah Al-Arabiah Al-Islamiah (offering the academic stream). The JMS aims to introduce the International Baccalaureate (IB) programme into the Madrasah Al-Arabiah Al-Islamiah by 2019. Students attending a madrasah are required to wear the traditional Malay attire, including the songkok for boys and tudong for girls, in contrast to mainstream government schools which ban religious headgear as Singapore is officially a secular state. For students who wish to attend a mainstream school, they may opt to take classes on weekends at the madrasah instead of enrolling full-time.
Question:  How many madrasahs are outside of Sinagapore?

Output: unanswerable


Input: Read this: For decades, the U.S. federal government strenuously tried to force Puerto Ricans to adopt English, to the extent of making them use English as the primary language of instruction in their high schools. It was completely unsuccessful, and retreated from that policy in 1948. Puerto Rico was able to maintain its Spanish language, culture, and identity because the relatively small, densely populated island was already home to nearly a million people at the time of the U.S. takeover, all of those spoke Spanish, and the territory was never hit with a massive influx of millions of English speakers like the vast territory acquired from Mexico 50 years earlier.
Question: How did Puerto Rico stay an English speaking territory?

Output:
unanswerable