You will be given a definition of a task first, then some input of the task.
Use a disfluent question or a proper question and find the answer to the question based on the given context or return None if an answer can't be found. A disfluent question is a question that has some interruptions in it while framing. A proper question is the correct form of the question without any disfluency.

proper question: What removed a hierarchical structure?
disfluent question: Who or no make that what removed a hierarchical structure?
context: In Japan, at the end of the Asuka period (538710) and the early Nara period (710794), the men who fulfilled roles similar to those of modern pharmacists were highly respected. The place of pharmacists in society was expressly defined in the Taiho Code (701) and re-stated in the Yoro Code (718). Ranked positions in the pre-Heian Imperial court were established; and this organizational structure remained largely intact until the Meiji Restoration (1868). In this highly stable hierarchy, the pharmacistsand even pharmacist assistantswere assigned status superior to all others in health-related fields such as physicians and acupuncturists. In the Imperial household, the pharmacist was even ranked above the two personal physicians of the Emperor.
Output:
None