#include <iostream>
#include <vector>
#include <fstream>

using namespace std;
ifstream in ("flip.in");
ofstream out ("flip.out");

int M[17][17];
bool sol[18];
int64_t rs = -1;
int n,m;

void backtrack(int step)
{
    if (step == n){
        int Mt[17][17];
        int64_t sum = 0;
        for (int i = 0; i<n; i++){
            if (sol[i]){
                for (int j = 0; j < m; j++){
                    Mt[i][j] = M[i][j] * (-1);
                }
            }
            else{
                for (int j = 0; j < m; j++){
                    Mt[i][j]= M[i][j];
                }
            }
        }
        for (int j = 0; j < m; j++){
            int64_t st = 0;
            for (int i = 0; i < n; i++){
                st += Mt[i][j];
            }
            if (st * (-1) > st)
                for (int i = 0; i < n; i++)
                    Mt[i][j] = Mt[i][j] * -1;
        }
        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++)
                sum+= Mt[i][j];
        if (sum > rs)
            rs = sum;
        return;
    }
    sol[step] = 1;
    backtrack(step+1);
    sol[step] = 0;
    backtrack(step+1);
}
int main()
{
    in >> n >> m;
    for (int i = 0; i< n; i++){
        for (int j = 0; j < m; j++){
            in >> M[i][j];
        }
    }
    backtrack(0);
    out << rs;
    return 0;
}