#include <fstream>

using namespace std;

ifstream fin("flip.in");
ofstream fout("flip.out");

int N, M, a[20][20], b[20][20], v[20], sum;

void copy()
{
    for (int i = 1; i <= N; ++i)
        for (int j = 1; j <= M; ++j)
            b[i][j] = a[i][j];
}

void rezolvare()
{
    copy();

    int s = 0;
    for (int i = 1; i <= N; ++i)
    {
        int s1 = 0, s2 = 0;
        for (int j = 1; j <= M; ++j)
        {
            if (v[j] == 1)
                b[i][j] *= -1;
            s1 += b[i][j];
            s2 += b[i][j] * -1;
        }
        if (s1 >= s2)
            s += s1;
        else
            s += s2;
    }
    if (s >= sum)
        sum = s;
}

void back(int k)
{
    if (k == M + 1)
    {
        rezolvare();
        return;
    }

    for (int i = 0; i <= 1; ++i)
    {
        v[k] = i;
        back(k + 1);
        v[k] = 0;
    }
}

int main()
{
    fin >> N >> M;
    for (int i = 1; i <= N; ++i)
        for (int j = 1; j <= M; ++j)
            fin >> a[i][j];

    sum = 0;
    back(1);

    fout << sum;

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