#include <iostream>
#include <fstream>
#include <cmath>

using namespace std;

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

int n, m, a[18][18], sol[17], fr[17], smax = 0;;

void prelucrare()
{
    int s = 0;
    for(int i=1; i<=n; i++)
    {
        int sumlin = 0;
        for(int j=1; j<=m; j++)
        {
            if(fr[j])
                a[i][j] = a[i][j]*(-1);
            sumlin += a[i][j];
        }
        s = s + abs(sumlin);
    }
    if(s>smax) smax = s;
}

void bkt(int p)
{
    for(int i=sol[p-1]+1; i<=n; i++)
    {
        sol[p] = i;
        fr[i] = 1;
        prelucrare();
        bkt(p+1);
        fr[i] = 0;
    }
}

int main()
{
    in>>n>>m;
    for(int i=1; i<=n; i++)
        for(int j=1; j<=m; j++)
            in>>a[i][j];
    bkt(1);
    out<<smax;
    return 0;
}