#include <fstream>

using namespace std;

ifstream f("flip.in");
ofstream g("flip.out");
int a[20][20];
int n, m;
int stack[20];
long long Max = -16000000001;

long long solution()
{
	long long sum = 0;
	long long s;
	for (int i = 1;i <= n;i++)
	{
		s = 0;
		for (int j = 1;j <= m;j++)
			if (stack[j])
				s += a[i][j] * -1;
			else
				s += a[i][j];
		if (s > -s)
			sum += s;
		else
			sum += -s;
	}
	return sum;
}

void backtracking(int k)
{
	if (k > m)
	{
		int x = solution();
		if (x > Max)
			Max = x;
		return;
	}
	stack[k] = 0;
	backtracking(k + 1);
	stack[k] = 1;
	backtracking(k + 1);
}

int main()
{
	f >> n >> m;
	for (int i = 1;i <= n;i++)
		for (int j = 1;j <= m;j++)
			f >> a[i][j];
	backtracking(1);
	g << Max;
	f.close();
	g.close();
	return 0;
}