You are painting a fence of length N. There are K people willing to paint a
portion of the fence. However, each person will only paint their given portion
of the fence if no one else has painted any part of the fence they want to
paint.

You want to minimize the amount of the fence that is not painted. Compute the
minimum amount of fence that will not be painted irrespective of how you
allocate workers to paint the fence.

Constraints:
[Division II]
1 <= N <= 100
1 <= K <= 10

[Division I]
1 <= N <= 10^18
1 <= K <= 2 * 10^5