#include <fstream>
using namespace std;

int a[16][16], sol[16], n, m, max_a = 0;

ifstream in("flip.in");
ofstream out("flip.out");

void citire();
void scriere();

int max_now()
{
    int sum_t = 0;

    for(int y = 0; y < n; y++)
    {
        int sum = 0;
        for(int x = 0; x < m; x++)
        {
            sum += a[y][x];
        }
        if(sum < 0) sum *= -1;

        sum_t += sum;
    }

    return sum_t;
}

void max_bt(int k)
{
    if(k == m)
    {
        int sum_n = max_now();
        if(sum_n > max_a)
            max_a = sum_n;
    }
    else
    {
        max_bt(k + 1);
        for(int y = 0; y < n; y++)
            a[y][k] *= -1;
        max_bt(k + 1);
    }
}

int main()
{
    citire();
    max_bt(0);
    scriere();

    return 0;
}

void citire()
{
    in >> n >> m;
    for(int i = 0; i < n; i++)
        for(int j = 0; j < m; j++)
        in >> a[i][j];
    in.close();
}

void scriere()
{
    out << max_a;
    out.close();
}