#include <bits/stdc++.h>

using namespace std;

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

int rows, cols, mat[17][17], mx = INT_MIN;

void calc(int r, int c) {
    int s = 0;
    for (int i = 1; i <= rows; ++i)
        for (int j = 1; j <= cols; ++j)
            if (i == r || j == c)
                s += mat[i][j] * -1;
            else
                s += mat[i][j];
    mx = max(mx, s);
}

void gen(int a, int b) {
    calc(a, b);
    if (a < rows)
        gen(a + 1, b);
    if (b < cols)
        gen(a, b + 1);
}

int main() {

    fin >> rows >> cols;
    for (int i = 1; i <= rows; ++i)
        for (int j = 1; j <= cols; ++j)
            fin >> mat[i][j];
    gen(1, 1);
    fout << mx;
    return 0;
}