#include <fstream>

using namespace std;

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

int maxim, n, m, M[25][25];

void bkt(int l)
{
    int sum, tot=0, i, j;
    if (l>n)
    {
        for (j=1; j<=m; j++)
        {
            sum=0;
            for (i=1; i<=n; i++)
                sum+=M[i][j];
            if (sum<0)
                sum *= -1;
            tot+=sum;
        }
        if (tot>maxim)
            maxim=tot;
    }
    else
    {
        for (i=1; i<=m; i++)
            M[l][i] *= -1;
        bkt(l+1);
        for (i=1; i<=m; i++)
            M[l][i] *= -1;
        bkt(l+1);
    }
}

int main()
{
    int i, j;
    fin>>n>>m;
    for (i=1; i<=n; i++)
        for (j=1; j<=m; j++)
        {
            fin>>M[i][j];
        }
    bkt(1);
    fout<<maxim;
    return 0;
}