Definition: Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
Input: Context: Gerard Debreu (French: (db); 4 July 1921 -- 31 December 2004) was a French-born American economist and mathematician.
Question: What is the birth date of Gerard Debreu?
Output:
4 july 1921