Ten men are fishing all in a row in
a large canoe. The seat in the middle of the boat is empty. The five men
in the front of the canoe want to exchange seats with the five men in back.
A person can move from his seat to the next empty seat or he can step over
one person without capsizing the canoe. What is the minimum number of moves
needed for the 5 men in front to change places with the 5 in back?