#include <fstream>
using namespace std;
int n, m, a[20][20];

void citire()
{
    ifstream in("flip.in");
    in >> n >> m;
    for(int i = 1; i <= n; ++i)
        for(int j = 1; j <= m; ++j)
            in >> a[i][j];
    in.close();
}

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

void afisare()
{
    ofstream out("flip.out");
    int sum = 0;
    for(int i = 1; i <= n; ++i) sum += a[i][0];
    out << sum << '\n';
    out.close();
}

int main()
{
    citire();
    calcul();
    afisare();
    return 0;
}