#include <iostream>
#include <fstream>
#include <math.h>

using namespace std;

int main()
{
	ifstream fin("flip.in");
	ofstream fout("flip.out");
	int n,m, s1 = 0, s2 = 0;
	int v[16][16];
	fin >> n >> m;
	for(int i = 0; i < n; i++)
		for (int j = 0; j < m; j++)
			fin >> v[i][j];

	for (int j = 0; j < m; ++j)
	{
		for (int i = 0; i < n; ++i)
		{
			s1 += v[i][j];
			s2 += -1*v[i][j];
		}
		if(s1 < s2)
			for (int i = 0; i < n; ++i)
				v[i][j] = -1*v[i][j];
		s1 = 0;
		s2 = 0;
	}

	for (int i = 0; i < n; ++i)
	{
		for (int j = 0; j < m; ++j)
		{
			s1 += v[i][j];
			s2 += -1*v[i][j];
		}
		if(s1 < s2)
		{
			for (int j = 0; j < n; ++j)
			{
				v[i][j] = -1*v[i][j];
			}
		}
		s1 = 0;
		s2 = 0;
	}

	for (int i = 0; i < n; ++i)
		for (int j = 0; j < m; ++j)
			s1 += v[i][j];

	fout << s1;
	return 0;
}