#include <bits/stdc++.h>
#define ll long long
using namespace std;
ifstream fin("flip.in");
ofstream fout("flip.out");
int n, m, rez, dim, mt[20][20], v2[20][20];

void solve(vector <int> v) {
    for (int p = 1; p <= dim; ++p) {
        int sum = 0;
        for (int i = 1; i <= n; ++i)
            for (int j = 1; j <= m; ++j) {
                int nr = mt[i][j];
                if (v2[p][i] == 1)
                    nr = -nr;
                if (v[j] == 1)
                    nr = -nr;
                sum += nr;
            }
        rez = max(rez, sum);
    }
    return;
}

void back(int pos, vector <int> v) {
    if (pos == m) {
        solve(v);
        return;
    }
    back(pos + 1, v);
    v[pos + 1] = 1;
    back(pos + 1, v);
    return;
}

void back2(int pos, vector <int> v) {
    if (pos == n) {
        ++dim;
        for (int i = 1; i <= n; ++i)
            v2[dim][i] = v[i];
        return;
    }
    back2(pos + 1, v);
    v[pos + 1] = 1;
    back2(pos + 1, v);
    return;
}

int main() {
    fin >> n >> m;
    for (int i = 1; i <= n; ++i)
        for (int j = 1; j <= m; ++j)
            fin >> mt[i][j];
    vector <int> v(20);
    back2(0, v);
    back(0, v);
    fout << rez;
    return 0;
}