Definition: In this task, you're given passages that contain mentions of the quantity of a particular object and are supposed to find out the answer for a given question. Craft one correct answer to the question given in input. Make sure your correct answer is consistent with the context, and properly gives the exact number relating to the query.
 In your answer, use as few words as possible from the given context. To be less repetitive, please vary your language for each question.

Positive Example 1 -
Input: Sentence: The New York metropolitan area is home to a self-identifying gay and bisexual community estimated at 568,903 individuals, the largest in the United States and one of the world's largest. Same-sex marriages in New York were legalized on June 24, 2011 and were authorized to take place beginning 30 days thereafter. 
Question: How many people identify as gay or bisexual in NYC?
Output: 568,903

Positive Example 2 -
Input: Sentence: The New York metropolitan area is home to a self-identifying gay and bisexual community estimated at 568,903 individuals, the largest in the United States and one of the world's largest. Same-sex marriages in New York were legalized on June 24, 2011 and were authorized to take place beginning 30 days thereafter. 
Question: Since Gay marriage became legal, how many days did people have to wait to marry?
Output: 30

Negative Example 1 -
Input: Sentence: The New York metropolitan area is home to a self-identifying gay and bisexual community estimated at 568,903 individuals, the largest in the United States and one of the world's largest. Same-sex marriages in New York were legalized on June 24, 2011 and were authorized to take place beginning 30 days thereafter. 
Question: Since Gay marriage became legal, how many days did people have to wait to marry?
Output: 45

Now complete the following example -
Input: Sentence: In 1919 Father James Burns became president of Notre Dame, and in three years he produced an academic revolution that brought the school up to national standards by adopting the elective system and moving away from the university's traditional scholastic and classical emphasis. By contrast, the Jesuit colleges, bastions of academic conservatism, were reluctant to move to a system of electives. Their graduates were shut out of Harvard Law School for that reason. Notre Dame continued to grow over the years, adding more colleges, programs, and sports teams. By 1921, with the addition of the College of Commerce, Notre Dame had grown from a small college to a university with five colleges and a professional law school. The university continued to expand and add new residence halls and buildings with each subsequent president. 
Question: Over how many years did the change to national standards undertaken at Notre Dame in the early 20th century take place?
Output: 



Answer: three years