A1269. [COCI-2012_2013-contest4]#5 RAZLIKA

Mirko's newest math homework assignment is a very difficult one! Given a sequence, V, of N integers, remove exactly K of them from the sequence. Let M be the largest difference of any two remaining numbers in the sequence, and m the smallest such difference. Select the K integers to be removed from V in such a way that the sum M + m is the smallest possible. Mirko isn't very good at math, so he has asked you to help him!

The first line of input contains two positive integers, N (3 ≤ N ≤ 1 000 000) and K (1 ≤ K ≤ N - 2).
The second line of input contains N space-separated positive integers – the sequence V (-5 000 000 ≤ Vi ≤ 5 000 000).

The first and only line of output must contain the smallest possible sum M + m.