#include <fstream>

using namespace std;

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

int n, m, i, j;
int a[18][18];
int smax;
int v[18];
bool u[18];

void verif()
{
    int s = 0, aux = 0;
    for (int j=1; j<=m; j++)
    {
        aux = 0;
        for (int i=1; i<=n; i++)
            if (!u[i])
                aux += a[i][j];
            else
                aux -= a[i][j];

        if(aux < 0)
            aux = -aux;

        s += aux;
    }
    smax = max(smax, s);
}

void bkt(int k)
{
    for (int i = v[k-1] + 1; i <= n; i++)
    {
        v[k] = i;
        u[i] = 1;

        verif();
        if (k < n)
            bkt(k + 1);

        u[i] = 0;
    }
}

int main()
{
    f >> n >> m;
    for (i=1; i<=n; i++)
        for (j=1; j<=m; j++)
        {
            f >> a[i][j];
            smax += a[i][j];
        }

    bkt(1);

    g << smax;

    return 0;
}