Freakin' news has recently claimed that they have discovered a civilization on mars and that they have established contact with the martians. Following is a summary of the dawn hour breakin' news on freakin' news :
Occassionally, the martian ministers feel the need to please their king. For this purpose, they give the king a trivial problem to solve and heap excessive praise upon him when he presents the correct solution.
This time they have given the king the following problem :
Given two positive integers n,k and n numbers a[1],a[2],...a[n] find the maximum of (b[1]a[1]+b[2]a[2]+.....b[n]a[n]) subject to the restrictions :
1) b[i] is either 1 or (-1), for all i, 1 ≤ i ≤ n.
2) Exactly k b[i]'s are 1. The remaining (n-k) b[i]'s are (-1).
To make the task even easier for the king, the ministers have given the king the sequence a[1],a[2],...a[n] sorted in non-decreasing order.

The king, being lazy, has outsourced the task to freakin' news. Your job is to do this task for freakin' news.

Input Format :

The first line of input contains a single integer n. The next line consists of n space seperated integers a[1], a[2], ... a[n]. The sequence a is guaranteed to be sorted in non-decreasing order.

Output Format :

On the only line of output, output a single integer : the maximum of (b[1]a[1]+b[2]a[2]+.....b[n]a[n]) subject to restrictions 1 and 2.

Constraints :

2 ≤ n ≤ 100
0 ≤ k ≤ n
|a[i]| ≤ 1000
The sequence a is sorted in non-decreasing order i.e. a[1] ≤ a[2] ≤ .... ≤ a[n]

Sample Input :
2 1
-4 -4

Sample Output :
0

Sample Input :
2 0
-2 5

Sample Output :
-3

Explanation :
1 : There are two possibilities for the sequence b : (+1,-1) and (-1,+1). Both lead to sum 0.
2 : There is only one possibility for the sequence b : (-1,-1). This leads to the sum -3.

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