#include <bits/stdc++.h>

using namespace std;

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

int n, m, a[17][17], b[17][17];

int main(){
    fin >> n >> m;
    for (int i = 1; i <= n; ++i){
        for (int j = 1; j <= m; ++j){
            fin >> a[i][j];
        }
    }
    int ans = -1e9;
    for (int stare = 0; stare < (1 << m); ++stare){
        for (int i = 1; i <= n; ++i){
            for (int j = 1; j <= m; ++j){
                b[i][j] = a[i][j];
            }
        }
        for (int j = 0; j < m; ++j){
            if ((stare >> j) & 1){
                for (int i = 1; i <= n; ++i){
                    b[i][j + 1] = b[i][j + 1] * (-1);
                }
            }
        }
        int sum = 0;
        for (int i = 1; i <= n; ++i){
            int sum1 = 0, sum2 = 0;
            for (int j = 1; j <= m; ++j){
                sum1 += b[i][j];
                sum2 += (b[i][j] * (-1));
            }
            sum += max(sum1, sum2);
        }
        ans = max(sum, ans);
    }
    fout << ans;
    fin.close();
    fout.close();
    return 0;
}