#include <fstream>

#define NMAX 17

using namespace std;

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

int a[NMAX][NMAX], v[NMAX];
int n, m, k, s, sum, maxim;

int main()
{
    cin >> n >> m;
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++)
            cin >> a[i][j];
    while(!v[0])
    {
        k = m;
        while(v[k])
        {
            v[k] = 0;
            k--;
        }
        v[k] = 1;
        s = 0;
        for(int i = 1; i <= n; i++)
        {
            sum = 0;
            for(int j = 1; j <= m; j++)
            {
                if(v[j])
                    sum += a[i][j];
                else
                    sum -= a[i][j];
            }
            if(sum >= 0)
                s += sum;
            else
                s -= sum;
        }
        if(s > maxim)
            maxim = s;
    }
    cout << maxim;

    return 0;
}