#include <iostream>
#include<fstream>

using namespace std;

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

int main()
{
    int n,m,i,j;
    int sum_linie[17]; // retinem suma elem de pe fiecare linie a matricei
    int sum_linie_comut[17];
    int sum_colana[17],sum_coloana_comut[17];
    int sol=0;
    f>>n>>m;
    int a[n][m];
    for(i=1;i<=n;i++)
    {
        sum_linie[i]=0;
        sum_linie_comut[i]=0;
        for(j=1;j<=m;j++)
        {
            f>>a[i][j];
            sum_linie[i]+=a[i][j];
            sum_linie_comut[i]-=a[i][j]; // transformam fiecare elem a[i][j] in opusul sau,si facem suma pe fiecare coloana
        }
        if(sum_linie[i]<sum_linie_comut[i])
            for(j=1;j<=n;j++)
                a[i][j]=-a[i][j];
    }

    for(j=1;j<=m;j++)
    {
        sum_colana[j]=0;
        sum_coloana_comut[j]=0;
        for(i=1;i<=n;i++)
        {
            sum_colana[j]+=a[i][j];
            sum_coloana_comut[j]-=a[i][j];
        }
        if(sum_colana[j]<sum_coloana_comut[j])
        {
            for(i=1;i<=n;i++)
                a[i][j]=-a[i][j];
        }
    }

    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
            sol+=a[i][j];
    cout<<sol;
    return 0;
}