#include <fstream>
using namespace std;

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

int c[17];
int a[17][17];
long long suma(-170000099), s;
int m, n;

void Ver();
void Back(int l);

int main()
{
	int i, j;
	fin >> m >> n;
	for (i = 1; i <= m; ++i)
		for (j = 1; j <= n; ++j)
			fin >> a[i][j];
	fin.close();
	
	Back(1);
	fout << suma << '\n';
	fin.close();
	fout.close();
	return 0;
}

void Back(int l)
{
	if (l > n)
	{
		Ver();
		return;
	}
	c[l] = 1;
	Back(l+1);
	c[l] = -1;
	Back(l+1);
}

void Ver()
{
	int i, j;
	long long ss(0);
	s = 0;
	for (i = 1; i <= m; ++i)
	{
		ss = 0;
		for (j = 1; j <= n; ++j)
			ss += a[i][j] * c[j];
		if (ss > 0) s += ss;
		else s -= ss;
	}
	
	if (s > suma) suma = s;
}