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
import math
import collections
import bisect
def get_ints(): return map(int, sys.stdin.readline().strip().split())
def get_list(): return list(map(int, sys.stdin.readline().strip().split()))
def get_string(): return sys.stdin.readline().strip()
n,k=get_list()
arr=get_list()
neg=[]
pos=[]
for i in arr:
    if i>0:
        pos.append(i)
    else:
        neg.append(i)
if len(neg)>0:
    neg.sort()
    limit=min(len(neg),k)
    for i in range(limit):
        neg[i]*=-1
        k-=1
if len(pos)>0:
    pos.sort()
ans=0
if len(pos)>0 and len(neg)>0:
    if pos[0]>neg[-1]:
        if k%2==1:
            pos[0]*=-1
    else:
        if k%2==1:
            neg[-1]*=-1
    ans=sum(pos)+sum(neg)
elif len(pos)>0:
    if k % 2 == 1:
        pos[0] *= -1
    ans=sum(pos)
else:
    if k % 2 == 1:
        neg[-1] *= -1
    ans=sum(neg)
print(ans)