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 = [int(j) for j in input().split()]
arr = [int(j) for j in input().split()]

def roma(arr, k):
    negatives = []
    pos = []
    for el in arr:
        if el < 0:
            negatives.append(el)
        else:
            pos.append(el)

    if len(negatives):

        if k <= len(negatives):
            negatives.sort()
            for i in range(k):
                negatives[i] *= -1
            p = sum(pos) if len(pos) else 0
            return p + sum(negatives)
        else:
            negatives = [k * -1 for k in negatives]
            negatives.sort()
            diff = k - len(negatives)
            if k % 2 != 0:
                negatives[0] *= -1
            p = sum(pos) if len(pos) else 0
            return p + sum(negatives)
    else:
        pos.sort()
        return sum(pos) if k % 2 == 0 else -pos[0] + sum(pos[1:])

print(roma(arr, k))