#include "bits/stdc++.h"
using namespace std;

void str(string &s, int n){
    for(int i = 0; i < n; i++){
        s += "0";
    }
}

void binare (string &s){
    for(int i = s.size() - 1; i >= 0; i--){
        if (s[i] == '0'){
            s[i] = '1';
            break;
        } else {
            s[i] = '0';
        }
    }
}

int main() {
    ifstream cin("flip.in");
    ofstream cout("flip.out");
    int n,m;
    cin >> n >> m;
    long s = 0;
    string c = "", r = "";
    
    vector<vector<int>> v(n, vector<int> (m, 0));
    for (int i = 0; i < n; i++){
        for(int j = 0; j < m; j++){
            cin >> v[i][j];
        }
    }
    str(r,m);
    str(c,n);
    for (int cl = 0; cl < pow(2,c.size()) - 1; cl++){
        binare(c);
        for (int rd = 0; rd < pow(2,r.size()) - 1; rd++){
            binare(r);
            long s1 = 0;
            for (int i = 0; i < n; i++){
                for(int j = 0; j < m; j++){
                    int d = 1;
                    if(c[i] == '0') {
                        d = -1;
                    }
                    if(r[j] == '0') {
                        d *= -1;
                    }
                    s1 += d  * v[i][j];
                }
            }
            if(cl == 0 || s < s1){
                s = s1;
            }
        }
    }
    cout << s;
    return 0;
}