#include <fstream>

#define NMAX 17

using namespace std;

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

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

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