#include <iostream>
#include <fstream>

using namespace std;

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

int sh(int a[17][17], int i, int m)
{
    int s=0, j;
    for(j=1; j<=m; j++)
        s = s + a[i][j];
    return s;
}

int main()
{
    int a[17][17], n, m, i, j, l, x, mx=0, s;

    f >> n >> m;
    for(i=1; i<=n; i++)
        for(j=1; j<=m; j++)
            f >> a[i][j];

    for(l=0; l<=70000; l++)
    {
        x = l;
        for(j=1; j<=m; j++)
        {
            if(x%2 == 1)
                for(i=1; i<=n; i++)
                    a[i][j] = -a[i][j];
            x = x/2;

        }

        s = 0;
        for(i=1; i<=n; i++)
            if(sh(a, i, m) < 0)
                s = s - sh(a, i, m);
            else
                s = s + sh(a, i, m);
        if(s > mx)
            mx = s;

        x = l;
        for(j=1; j<=m; j++)
        {
            if(x%2 == 1)
                for(i=1; i<=n; i++)
                    a[i][j] = -a[i][j];
            x = x/2;

        }

    }

    g << mx;

    return 0;
}