#include <fstream>
#include <iostream>

using namespace std;

const int maxn = 20;

int n, m, a[maxn][maxn];

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

    fin >> n >> m;
    int ans = 0;
    for(int i = 0 ; i < n ; ++ i)
        for(int j = 0 ; j < m ; ++ j) {
            fin >> a[i][j];
            ans += a[i][j];
        }
    for(int conf = 0 ; conf < (1 << m) ; ++ conf) {
        int actsum = 0;
        for(int i = 0 ; i < n ; ++ i) {
            int sum = 0; 
            for(int j = 0 ; j < m ; ++ j)
                if(conf & (1 << j))
                    sum += -a[i][j];
                else
                    sum += a[i][j];
            actsum += max(sum, -sum);
        }
        ans = max(ans, actsum);
    }
    fout << ans << '\n';
}