In this task, you're given a statement, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.

Context: first for a short time from 1444 to September 1446, and later from February 1451 to 1481. Link Information: was an Ottoman Sultan who ruled from August 1444 to September 1446, and then later from February 1451 to May 1481. Question: Where was the Ottoman Empire's capital when Mehmed the Conqueror was Sultan?
Answer: Constantinople