This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Example Input: Passage: Indian astronomer and mathematician Aryabhata (476-550), in his Aryabhatiya (499) introduced a number of trigonometric functions (including sine, versine, cosine and inverse sine), trigonometric tables, and techniques and algorithms of algebra. In 628 AD, Brahmagupta suggested that gravity was a force of attraction. He also lucidly explained the use of zero as both a placeholder and a decimal digit, along with the Hindu-Arabic numeral system now used universally throughout the world. Arabic translations of the two astronomers' texts were soon available in the Islamic world, introducing what would become Arabic numerals to the Islamic World by the 9th century. During the 14th–16th centuries, the Kerala school of astronomy and mathematics made significant advances in astronomy and especially mathematics, including fields such as trigonometry and analysis. In particular, Madhava of Sangamagrama is considered the "founder of mathematical analysis". Question: What did Brahmagupta use the number zero for?
Example Output: a placeholder and a decimal digit

Example Input: Passage: Caesar became consul in 59 BC. His colleague, Marcus Calpurnius Bibulus, was an extreme aristocrat. Caesar submitted the laws that he had promised Pompey to the assemblies. Bibulus attempted to obstruct the enactment of these laws, and so Caesar used violent means to ensure their passage. Caesar was then made governor of three provinces. He facilitated the election of the former patrician Publius Clodius Pulcher to the tribunate for 58 BC. Clodius set about depriving Caesar's senatorial enemies of two of their more obstinate leaders in Cato and Cicero. Clodius was a bitter opponent of Cicero because Cicero had testified against him in a sacrilege case. Clodius attempted to try Cicero for executing citizens without a trial during the Catiline conspiracy, resulting in Cicero going into self-imposed exile and his house in Rome being burnt down. Clodius also passed a bill that forced Cato to lead the invasion of Cyprus which would keep him away from Rome for some years. Clodius also passed a law to expand the previous partial grain subsidy to a fully free grain dole for citizens. Question: Who enacted a law that would increase the partial grain subsidy?
Example Output: Clodius

Example Input: Passage: Von Neumann introduced the study of rings of operators, through the von Neumann algebras. A von Neumann algebra is a *-algebra of bounded operators on a Hilbert space that is closed in the weak operator topology and contains the identity operator. The von Neumann bicommutant theorem shows that the analytic definition is equivalent to a purely algebraic definition as an algebra of symmetries. The direct integral was introduced in 1949 by John von Neumann. One of von Neumann's analyses was to reduce the classification of von Neumann algebras on separable Hilbert spaces to the classification of factors. Question: When was direct integral introduced by von Neumann?
Example Output:
1949

