#include <fstream>
#include <algorithm>

using namespace std;

ifstream fin("input.txt");
ofstream fout("output.txt");

int muie(int a[16][16], int n, int m) {
    int smax = 0;
    for (int i = 0; i < (1 << n); ++i)
        for (int j = 0; j < (1 << m); ++j) {
            int b[16][16];
            for (int x = 0; x < n; ++x)
                for (int y = 0; y < m; ++y)
                    b[x][y] = a[x][y];
            for (int x = 0; x < n; ++x)
                if (i & (1 << n))
                    for (int y = 0; y < m; ++y)
                        b[x][y] *= -1;
            for (int y = 0; y < m; ++y)
                if (j & (1 << m))
                    for (int x = 0; x < m; ++x)
                        b[x][y] *= -1;
            int s = 0;
            for (int x = 0; x < n; ++x)
                for (int y = 0; y < m; ++y)
                    s += b[x][y];
            smax = max(smax, s);
        }
    return smax;
}

int n, m, a[16][16], i, j;

int main()
{
    fin >> n >> m;
    for (i = 0; i < n; ++i)
        for (j = 0; j < m; ++j)
            fin >> a[i][j];
    fout << muie(a, n, m);

    fin.close();
    fout.close();
    return 0;
}