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: Eygilo, the founder of Prum Abbey, left his own establishment to become abbot of Flavigny in 860 Link Information: founded by the Frankish widow Bertrada the elder and her son Charibert, Count of Laon, on 23 June 720 Question: How long had Prum Abbey existed when Eygilo left to become the abbot of Flavigny?
Answer: 140