#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;
    g.close(); f.close(); return 0;
}