Definition: The answer will be 'yes' if the provided sentence contains an explicit mention that answers the given question. Otherwise, the answer should be 'no'. Instances where the answer is implied from the sentence using "instinct" or "common sense" (as opposed to being written explicitly in the sentence) should be labeled as 'no'.
Input: Sentence: Mr. Barco has refused U.S. troops or advisers but has accepted U.S. military aid. 
Question: When did he begin to accept the military aid?

Yes.