#include <iostream>
#include <stdlib.h>
#include <fstream>
using namespace std;

int a[20][20], st[17], maxim = -99999999, n, m;

void back (int k)
{
    if (k == m + 1)
    {
        int s = 0;
        for (int i = 1; i <= n; i++)
        {
            int s_l = 0;
            for (int j = 1; j <= m; j++)
                s_l += a[i][j];
            s += abs(s_l);
        }
        if (s > maxim)
            maxim = s;
        return;
    }
    for (int i = 0; i < 2; i++)
    {
        st[k] = i;
        if (st[k] == 1)
        {
            for (int j = 1; j <= n; j++)
                a[j][k] = -a[j][k];
        }
        back(k + 1);
        if (st[k] == 1)
        {
            for (int j = 1; j <= n; j++)
                a[j][k] = -a[j][k];
        }
    }
}

int main()
{
    ifstream in("flip.in");
    ofstream out("flip.out");
    in >> n >> m;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
            in >> a[i][j];
    in.close();
    back(1);
    out << maxim;
    out.close();
    return 0;
}