#include <fstream>
#include <algorithm>
#include <cmath>
#define nmax 18
using namespace std;
ifstream fin("flip.in");
ofstream fout("flip.out");

int n, m, matrix[nmax][nmax], max_sum;

void assign_to_column(int j) {
    for (int i = 1; i <= n; ++i)
        matrix[i][j] *= -1;
}

void verifier_and_maker() {
    int total = 0;
    for (int i = 1; i <= n; ++i) {
        int sum = 0;
        for (int j = 1; j <= m; ++j)
            sum += matrix[i][j];
        total += abs(sum);
    }
    max_sum = max(max_sum, total);
}

void back_tracking(int position) {
    assign_to_column(position);
    if (position != m)
        back_tracking(position + 1);
    else
        verifier_and_maker();
    assign_to_column(position);
    if (position != m)
        back_tracking(position + 1);
    else
        verifier_and_maker();
}

void read_input() {
    fin >> n >> m;
    for (int i = 1; i <= n; ++i)
        for (int j = 1; j <= m; ++j)
            fin >> matrix[i][j];
    back_tracking(1);
    fout << max_sum;
}

int main()
{
    read_input();
    return 0;
}