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

#define inf 1e9;

int board[20][20];
int line_switch[20];
int n, m, i, j;
int _max = -inf;

void select_cols()
{
    int sum = 0, current = 0, i, j;

    for (j = 0; j < m; ++j) {
        current = 0;

        for (i = 0; i < n; ++i)
            current += (line_switch[i] * board[i][j]);

        if (current < 0)
            current *= (-1);

        sum += current;
    }

    if (sum > _max)
        _max = sum;
}

void backtr(int pos)
{
    if (pos == n) {
        select_cols();
        return;
    }
    /// +
    backtr(pos + 1);

    /// -
    line_switch[pos] = -1;
    backtr(pos + 1);
    line_switch[pos] = 1;

}

int main()
{
    ifstream in("flip.in");
    ofstream out("flip.out");

    in >> n >> m;
    for (i = 0; i < n; ++i) {
        line_switch[i] = 1;

        for (j = 0; j < m; ++j)
            in >> board[i][j];
    }

    backtr(0);

    out << _max << '\n';

    in.close();
    out.close();

    return 0;
}