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.
n,k = map(int,input().split())
incomes = list(map(int,input().split()))
last_neg = -1 
hasZeroz = False
for i in range(n):
  if incomes[i] <0:
    last_neg = i
  if incomes[i] == 0:
    hasZeroz = True

if last_neg == -1 :
  if k %2 == 0:
    print(sum(incomes))
  else:
    print(sum(incomes)-incomes[0]*2)
else :
  if k <= last_neg+1:
    # print('k less')
    print(-1* sum(incomes[:k])+sum(incomes[k:]))
  else:
    if hasZeroz or (k - last_neg+1) %2 == 0:
      print(-1*sum(incomes[0:last_neg+1])+sum(incomes[last_neg+1:]))
    else :
      # print('am alright')
      print(-1*sum(incomes[:last_neg]) + sum(incomes[last_neg:])  )

# if k <=last_neg:




# 12 28
# -6652 -6621 -6471 -5559 -5326 -4551 -4401 -4326 -3294 -1175 -1069 -43


