Statement

William is a famous urban planner and he has been commissioned the design of a new high road to connect Pordenone to Campobasso. There is only a small problem: he has to build the road across a park where there are N very important statues. These statues are placed along a circumference at distinct integer angles A_i (from 0 to 2K-1). The road must cross the center of the circle (like a diameter) and it is wide such that, if it starts at angle p, it covers all the statues between p and p+L-1 and between p+K and p+K+L-1 (extremes included). William can design the road at any angle, but he wants to find the minimum number of ancient monuments he is forced to demolish in order to build it.