Generate a correct and concise answer for the question based on the words in the context.

Context : Vice Admiral Russell Willson (December 27, 1883, Fredonia, New York -- June 6, 1948, Chevy Chase, Maryland) was a flag officer of the United States Navy and inventor of the Navy Cipher Box (also called 'Naval Cipher Box' or 'Navy Code Box') issued in 1917.
Question : What military branch is Russell Willson?
United States Navy