#include <fstream>
#include <cmath>

int main()
{
    int n, m, i, j, k, s, maxcur = 0, max1 = 0;
    ifstream in("flip.in");
    ofstream out("flip.out");
    int v[17][17], nis[16];

    in >> n >> m;
    for (i = 1; i <= n; i++)
        for (j = 1; j <= m; j++)
            in >> v[i][j];
    for (i = 0; i < (1 << n); i++)
    {
        maxcur = 0;
        for (j = 0; j < n; j++)
            nis[j] = (1 << j) & i;
        for (k = 1; k <= m; k++)
        {
            s = 0;
            for (j = 1; j <= n; j++)
                if (nis[j])
                    s += 0 - v[j][k];
                else
                    s += v[j][k];
            if (s < 0)
                maxcur += 0 - s;
            else
                maxcur += s;
        }
        max1 = max(max1, maxcur);
    }
    out << max1;
    return 0;
}