#include <fstream>
using namespace std;

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

int m, n;
int H[17][17], v[17];
int bestSum = -0x7fffffff;

void bt(int k)
{
    long long sum, aux;
    if (k == n+1)
    {
        sum = 0;
        for (int i = 1; i <= m; i++)
        {
            aux = 0;
            for (int j = 1; j <= n; j++)
                aux = aux + H[j][i]*v[j];
            if (aux < 0)
                sum = sum - aux;
            else
                sum = sum + aux;
        }
        if (bestSum < sum)
            bestSum = sum;
        return;
    }
    v[k] = 1;
    bt(k+1);
    v[k] = -1;
    bt(k+1);
}

int main()
{
    in >> n >> m;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
            in >> H[i][j];
    bt(1);
    out << bestSum;
    return 0;
}