#include<bits/stdc++.h>

using namespace std;

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

#define NMAX 20

int c[NMAX],l[NMAX];
int ma[NMAX][NMAX];
int n,m;
int sol[NMAX];
int maxim = 0;

void calc(int k)
{
    int sum = 0;
    for(int i=1;i<k;i++)
    {
        sum+= l[i] * sol[i];
    }
    if(sum > maxim)
        maxim = sum;
}

void bkt(int k)
{
    if(k == n+1)
    {
        calc(k);
    }
    else
    {
        sol[k] = 1;
        bkt(k+1);
        sol[k] = -1;
        bkt(k+1);
    }

}


int main()
{
    fin>>n>>m;
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=m;j++)
        {
            int x;
            fin>>x;
            ma[i][j] = x;
            c[j]+=x;
        }
    }

    for(int i=1;i<=m;i++)
    {
        if(c[i] < 0)
        {
            for(int j=1;j<=n;j++)
            {
                ma[j][i] *= -1;
            }
        }
    }

    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=m;j++)
        {
            //cout<<ma[i][j]<<" ";
            l[i] += ma[i][j];
        }
        //cout<<l[i]<<endl;
        //cout<<endl;
    }



    bkt(1);

    fout<<maxim;
}