#include<stdio.h>
using namespace std;
const int L = 17;
int mat[L][L], n, m;
int stiva[L], c, maxim = -20000000;
void prelucrare()
{
    int i, j, sum, s = 0;
    for (i = 1; i <= c; i++)
    {
        for (j = 1; j <= m; j++)
            mat[stiva[i]][j] *= -1;
    }
    for (j = 1; j <= m; j++)
    {
        sum = 0;
        for (i = 1; i <= n; i++)
            sum += mat[i][j];
        if (sum < 0)
            sum *= -1;
        s += sum;
    }
    for (i = 1; i <= c; i++)
    {
        for (j = 1; j <= m; j++)
            mat[stiva[i]][j] *= -1;
    }
    if (s > maxim)
        maxim = s;
}
void bkt(int poz)
{
    if (poz <= n)//
    {
        int i;
        for (i = poz; i <= n; i++)
        {
            stiva[++c] = i;
            prelucrare();
            bkt(poz + 1);
            c--;
        }
    }
}
int main ()
{
    FILE *in, *out;
    in = fopen ("flip.in", "r");
    out = fopen ("flip.out", "w");
    fscanf (in, "%d%d", &n, &m);
    int i, j;
    for (i = 1; i <= n; i++)
        for (j = 1; j <= m; j++)
            fscanf (in, "%d", &mat[i][j]);
    bkt(1);
    fprintf (out, "%d", maxim);
    return 0;
}