#include <fstream>
#include <vector>
#include <climits>

using namespace std;

int a[20][20], n, m, sol = INT_MIN;
vector<int> subset;

void solve() {
    for(int line : subset) {
        for(int j = 1; j <= m; j++) {
            a[line][j] *= -1;
        }
    }
    int sum_total = 0;
    for(int j = 1; j <= m; j++) {
        int sum_col = 0;
        for(int i = 1; i <= n; i++) {
            sum_col += a[i][j];
        }
        sum_total += abs(sum_col);
    }
    sol = max(sol, sum_total);
    // undo
    for(int line : subset) {
        for(int j = 1; j <= m; j++) {
            a[line][j] *= -1;
        }
    }
}

void backtrack(int val) {
    if(val == n + 1) {
        solve();
        return;
    }
    subset.push_back(val);
    backtrack(val + 1);
    subset.pop_back();
    backtrack(val + 1);
}

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 >> a[i][j];
        }
    }
    backtrack(1);
    fout << sol;
    return 0;
}