#include <iostream>
#include <fstream>

using namespace std;

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

int n,m,a[17][17],sm,x[17];

void f1()
{
    int S=0;
    for (int i=1;i<=n;i++)
    {
        int s=0;
        for (int j=1;j<=m;j++){
            if (x[j]) s=s-a[i][j];
            else s+=a[i][j];
        }
        if (s < 0) S=S-s;
        else S=S+s;
    }
    if (S>sm) sm=S;
}

void f2()
{
    int k=1;
    x[k]=-1;
    do
    {
        while (x[k]<1)
        {
            x[k]++;
            if (k==m) f1();
            else x[k++]=-1;
        }
        k--;
    } while (k);
}

int main()
{
    fin>>n>>m;
    for(int i=1;i<=n;i++){
        for (int j=1;j<=m;j++){
            fin>>a[i][j];
        }
    }
    f2();
    fout<<sm;
    return 0;
}