Definition: In this task, you're given a passage, 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'.
Input: Passage: Pocock joined the Royal Air Force in 1974. He served as Officer Commanding Support Wing at the joint RAF and Army base at Akrotiri before becoming briefing officer to the Chief of the Air Staff. He went on to be Group Captain in charge of the RAF estate in 1996, Air Commodore Plans at RAF Logistics Command in 1997 and Air Commodore Plans and Policy at RAF Personnel and Training Command in 1999. He became Officer responsible for Defence Pay & Allowances in 2000, Head of the Service Personnel Change Programme with promotion to air vice-marshal in January 2003 before serving as Defence Services Secretary and Assistant Chief of Defence Staff (Personnel and Reserves) from 2004 to 2005. He was promoted to air marshal in July 2005 and became Deputy Chief of the Defence Staff (Personnel) and retired in 2007. He was appointed Companion of the Order of the Bath (CB) in the 2008 New Year Honours.
Link Information: The Royal Air Force (RAF) is the United Kingdom's aerial warfare force. It was formed towards the end of the First World War on 1 April 1918 Question: How long had the Royal Air Force been around when he joined?
Output:
Answer: 56