#include <fstream>
using namespace std;
ifstream f("flip.in");
ofstream g("flip.out");
int n, m, a[17][17], smax, x[17];
void rezolva()
{
    int S = 0;
    for (int i = 1; i <= n; ++i)
    {
        int s = 0;
        for (int j = 1; j <= m; ++j)
            if (x[j]) s -= a[i][j]; else s += a[i][j];
        if (s < 0) S -= s; else S += s;
    }
    if (S > smax) smax = S;
}
void back()
{
    int k = 1; x[k] = -1;
    do
    {
        while (x[k] < 1)
        {
            x[k]++;
            if (k == m) rezolva(); else x[++k] = -1;
        }
        k--;
    } while (k);
}
int main()
{
    f >> n >> m;
    for (int i = 1; i <= n; ++i)
        for (int j = 1; j <= m; ++j) f >> a[i][j];
    back();
    g << smax;
    return 0;
}