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 heapq


def solver():
    n, k = map(int, input().split())
    arr = [int(x) for x in input().split()]
    cnt_neg = 0
    for i in range(len(arr)):
        if arr[i] <= 0:
            cnt_neg += 1
        else:
            break
    if cnt_neg >= k:
        max_sum = 0
        for i in range(len(arr)):
            if k > 0:
                max_sum = max_sum - arr[i]
                k -= 1
            else:
                max_sum = max_sum + arr[i]
        print(max_sum)
    else:
        # k > cnt_neg
        max_sum = 0
        for i in range(len(arr)):
            if i < cnt_neg - 1:
                max_sum = max_sum - arr[i]
            elif i == cnt_neg - 1:
                max_sum = max_sum + ((-1) ** (k - cnt_neg)) * arr[i]
            else:
                max_sum = max_sum + arr[i]
        print(max_sum)


if __name__ == '__main__':
    solver()
