Question 70
Let $n$ be a positive integer. There are $2n$ knights sitting at a round table. They consist of $n$ pair of partners, each pair of which wishes to shake hands. A pair can shake hands only with next to each other. Every minute, one pair of adjacent knights swaps places. Find the minimum number of exchanges of adjacent knights such that, regardless of the initial arrangement, every knight can meet her partner and shake hands at some moment.