#include <fstream>
#define MAX 17
using namespace std;
int a[MAX][MAX], v[MAX];
int n,m,s,sum,maxim;

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

int main()
{
    fin >> n >> m;
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++)
            fin >> a[i][j];

    while (v[1] == 0){
        int 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;
    }
    fout << maxim <<"\n";
    return 0;
}