#include <fstream>

std::ifstream in("flip.in");
std::ofstream out("flip.out");

int v[16][16], n, m, max = 0;

void bck(int l) {
    if (l == n) {
        int sum = 0;
        for (int j = 0; j < m; j++) {
            int psum = 0;
            for (int i = 0; i < n; i++) psum += v[i][j];
            if (psum < 0) psum *= -1;
            sum += psum;
        }
        if (sum > max) max = sum;
        return;
    }

    bck(l + 1);

    for (int j = 0; j < m; j++) v[l][j] *= -1;

    bck(l + 1);

    for (int j = 0; j < m; j++) v[l][j] *= -1;

    return;
}

int main() {
    in >> n >> m;

    for (int i = 0; i < n; i++)
        for (int j = 0; j < m; j++) in >> v[i][j];

    bck(0);

    out << max;
}