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=map(int,input().split())
l = list(map(int,input().split()))
a = []
b = []

if n==1:
	if k%2==0:
		print(l[0])
	else:
		print(l[0]*(-1))
else:
	for i in range(n):
		if l[i]<0:
			a.append(l[i])
		else:
			b.append(l[i])
	
	a.sort()
	
	if len(a)>0 and k<len(a):
		for i in range(k):
			a[i]=a[i]*(-1)
	else:
		for i in range(len(a)):
			a[i]=a[i]*(-1)
		
	z = max(0,k-len(a))
	t = z%2
	ans = a+b
	ans.sort()
	if t:
		ans[0]=ans[0]*(-1)
	
	
	print(sum(ans))