#include <iostream>
#include <fstream>
using namespace std;
int main() {
	ifstream f("flip.in");
	ofstream g("flip.out");
	int m, n, v[101][101], s1 = 0, s2 = 0, i, j, v1[101][101], s3 = 0, s4 = 0;
	f >> n >> m;
	for (i = 1; i <= n; i++)
		for (j = 1; j <= m; j++)f >> v[i][j];
	for (i = 1; i <= n; i++) {
		s1 = 0;
		s2 = 0;
		for (j = 1; j <= m; j++)
		{
			s1 = s1 + v[i][j];
			s2 = s2 + (-1) * v[i][j];
		}
		if (s1 < s2)for (j = 1; j <= m; j++)v[i][j] = (-1) * v[i][j];
	}
	s1 = 0;
	s2 = 0;

	for (j = 1; j <= m; j++) {
		s1 = 0;
		s2 = 0;
		for (i = 1; i <= n; i++)
		{
			s1 = s1 + v[i][j];
			s2 = s2 + (-1) * v[i][j];
		}
		if (s1 < s2)for (i = 1; i <= n; i++)v[i][j] = (-1) * v[i][j];
	}
	for (i = 1; i <= n; i++)
		for (j = 1; j <= m; j++)s4 = s4 + v[i][j];
	g << s4;
}