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 = list(map(int, input().split()))

incomes = list(map(int, input().split()))

incomes.sort()

total = 0

negative_incomes = []

positive_incomes = []

for income in incomes:
    if income < 0:
        negative_incomes.append(income)
    else:
        positive_incomes.append(income)


negative_incomes_len = len(negative_incomes)

m = negative_incomes_len - k

if m >= 0:
    total = total - sum(negative_incomes[0:k]) + sum(negative_incomes[k:]) + sum(positive_incomes)
else:
    if abs(m) % 2 == 0:
        total = total - sum(negative_incomes) + sum(positive_incomes)
    else:
        if negative_incomes_len > 0:
            if abs(max(negative_incomes)) < min(positive_incomes):
                total = total - sum(negative_incomes[:-1]) + negative_incomes[-1] + sum(positive_incomes)
            else:
                total = total - sum(negative_incomes) + sum(positive_incomes[1:]) - positive_incomes[0]
        else:
            total = total - sum(negative_incomes) + sum(positive_incomes[1:]) - positive_incomes[0]

print(total)
