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 sys
input = sys.stdin.readline
import bisect

n, k = map(int, input().split())
w = list(map(int, input().split()))
x = bisect.bisect(w, -1)
w1 = w[:x]
w2 = w[x:]
if k <= x:
    print(sum(w2) - sum(w1[:k]) + sum(w1[k:]))
else:
    c = sum(w2)-sum(w1)
    if 0 in w:
        print(c)
    else:
        if (k-x) % 2:
            m = min(abs(max(w1)), min(w2))
            print(c-m)
        else:
            print(c)