#include <iostream>
#include <fstream>
#include <math.h>

using namespace std;

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

int a[100][100], n, m, sum, sumx;

int calcul()
{
    int aux, sumx = 0;
    for (int i = 1; i <= n; i++)
    {
        aux = 0;
        for(int j = 1; j <= m; j++)
            aux += a[i][j];

        if (aux < 0)
        {
            aux *= -1;
        }

        sumx += aux;
    }
}

int backtrack (int k)
{
    if (k > m)
    {
        calcul();
        sum = max(sum, sumx);
    }
    else
    {
        backtrack(k+1);
        for (int i = 1; i <= n; i++)
        {
            a[i][k] *= -1;
        }
        backtrack(k+1);
    }
}

int main()
{
    fin >> n >> m;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= m; j++)
        {
            fin >> a[i][j];
        }
    }
    backtrack(1);
    fout << sum;
    return 0;
}