#include<bits/stdc++.h>
using namespace std;
int n, m, a[20][20], ans, sum[20];
ifstream f("flip.in");
ofstream g("flip.out");
void dfs(int x, int s) {
    if (x == n) {
        ans = max(ans, s);
        return;
    }
    for (int i = 0; i < m; i++) {
        int t = sum[i];
        for (int j = 0; j < n; j++)
            t += a[j][i] * pow(-1, x + j);
        dfs(x + 1, s + t);
    }
}
int main() {
    f >> n >> m;
    for (int i = 0; i < n; i++)
        for (int j = 0; j < m; j++) {
            f >> a[i][j];
            sum[j] += a[i][j];
        }
    dfs(0, 0);
    g << ans << endl;
    return 0;
}