#include<fstream>
using namespace std;
int a[20][20], i, m, n, s;
ifstream f("flip.in");
ofstream d("flip.out");
int main()
{
    long i, j, s1, r, t;
    f >> n;
    f >> m;
    for (i = 0; i < n; i++)
        for (j = 0; j < m; j++)
            f >> a[i][j];
    for (r = 0; r < (1 << m); r++)
    {
        s1 = 0;
        for (i = 0; i < n; i++)
        {
            for (t = j = 0; j < m; j++)
                if (r & (1 << j))t += -a[i][j];
                else t += a[i][j];
            if (t > -t)s1 += t;
            else s1 += -t;
        }
        if (s1 > s)s = s1;
    }
    d << s;
    return 0;
}