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.
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# Author: eloyhz
# Date: Sep/23/2020
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if __name__ == '__main__':
    n, k = [int(x) for x in input().split()]
    a = [int(x) for x in input().split()]
    s = 0
    for x in a:
        if x < 0:
            s += 1
    if s == 0:
        for _ in range(k):
            a[0] *= -1
    elif k <= s:
        for i in range(k):
            a[i] *= -1
    else:
        r = k - s
        for i in range(s):
            a[i] *= -1
        if i == n:
            i -= 1
        elif a[i - 1] < a[i]:
            i -= 1
        while r > 0:
            a[i] *= -1
            r -= 1
    print(sum(a))


