#include <bits/stdc++.h>

using namespace std;

int n, m, v[20][20], col[20], mx = -2000000000;

void bkt(int k)
{
    int sum = 0;
    for (int i = 1; i <= m; ++i)
        sum += abs(col[i]);
    mx = max(mx, sum);
    for (int i = k+1; i <= n; ++i){
        for (int j = 1; j <= m; ++j){
            v[i][j] *= -1;
            col[j] += 2*v[i][j];
        }
        bkt(i);
        for (int j = 1; j <= m; ++j){
            v[i][j] *= -1;
            col[j] += 2*v[i][j];
        }
    }
}

int main()
{
    ifstream fin ("flip.in");
    ofstream fout ("flip.out");
    fin >> n >> m;
    for (int i = 1; i <= n; ++i)
        for (int j = 1; j <= m; ++j){
            fin >> v[i][j];
            col[j] += v[i][j];
        }
    bkt(0);
    fout << mx << "\n";
    return 0;
}