Detailed Instructions: 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'.
Q: Context: Charlemagne allied with Khan Krum of Bulgaria and the Croatian duke Vojnomir Link Information: none Question: Which ruler that Charlemagne allied with ruled for a longer period of time?
A:
Answer: none