Roma works in a company that sells TVs. Now he has to prepare a report for the last year.

Roma has got a list of the company's incomes. The list is a sequence that consists of *n* integers. The total income of the company is the sum of all integers in sequence. Roma decided to perform exactly *k* changes of signs of several numbers in the sequence. He can also change the sign of a number one, two or more times.

The operation of changing a number's sign is the operation of multiplying this number by -1.

Help Roma perform the changes so as to make the total income of the company (the sum of numbers in the resulting sequence) maximum. Note that Roma should perform exactly *k* changes.
The first line contains two integers *n* and *k* (1 ≤ *n*, *k* ≤ 10<sup class="upper-index">5</sup>), showing, how many numbers are in the sequence and how many swaps are to be made.

The second line contains a non-decreasing sequence, consisting of *n* integers *a*<sub class="lower-index">*i*</sub> (|*a*<sub class="lower-index">*i*</sub>| ≤ 10<sup class="upper-index">4</sup>).

The numbers in the lines are separated by single spaces. Please note that the given sequence is sorted in non-decreasing order.
# import sys
import math
# sys.stdin = open('input1.txt', 'r') 
# sys.stdout = open('output1.txt', 'w')
n1,k1=input().split(" ")
n=int(n1)
k=int(k1)
ar1=input().split(" ")
ar=[]
for i in  ar1 :
    ar.append(int(i))
count_neg=0
for i in ar :
    if i < 0 :
        count_neg+=1
s=0
if count_neg == k :
    for i in ar :
        s+=abs(i)
elif count_neg > k :
    li_neg_to_pos=[]
    li_neg=[]
    
    rev_ar=ar
    #print(rev_ar)
    for i in rev_ar :
        if i < 0 :
            if len(li_neg_to_pos) < k :
                li_neg_to_pos.append(abs(i))
            else :
                li_neg.append(i)
    
    for i in ar :
        if i >= 0 :
            s+=i
    
    for i in li_neg_to_pos :
        s+=i
    for i in li_neg :
        s+=i
elif count_neg < k :
    ar.reverse()
    
    c=0
    for i in ar :
        if i <= 0 :
            c=i
            break
    for i in ar :
        if i != c :
            s+=abs(i)
    c=math.pow(-1,k-count_neg) * c
    s+=c

print(int(s))



            
            
        






    

        






    





