wwww

// This file is a "Hello, world!" in C++ language by GCC for wandbox.
#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;
long long maxi (long long int a, long long b)
{
    return a > b ? a : b;
}
int main()
{
    unsigned int N, k;
    cin >> N >> k;
    vector<unsigned int> south;
    vector<unsigned int> north;

    long long int sum = 0;
    int input;
    for (unsigned int i = 0; i < N; i++)
    {
        cin >> input;
        sum += input;
        if (input > 0)
        {
            north.push_back(input);
        } else {
            south.push_back(abs(input));
        }
    };
    sort(north.begin(), north.end());
    sort(south.begin(), south.end());

    unsigned long long int sum_south = 0, sum_north = 0;
    for (unsigned int i = south.size() - 1; ; i--)
    {
        sum_south += south[i];
        if (i == 0 || i == south.size() - k) break;
    };
    for (unsigned int i = north.size() - 1; ; i--)
    {
        sum_north += north[i];
        if (i == 0 || i == north.size() - k) break;
    };
    cout<< maxi (sum - 2*sum_north, sum + 2*sum_south);
    return 0;
}

// GCC reference:
//   https://gcc.gnu.org/

// C++ language references:
//   https://msdn.microsoft.com/library/3bstk3k5.aspx
//   http://www.cplusplus.com/
//   https://isocpp.org/
//   http://www.open-std.org/jtc1/sc22/wg21/

// Boost libraries references:
//   http://www.boost.org/doc/