#include <fstream>

using namespace std;

int a[20][20], b[20][20];
int v[20];
int n, i, s, sc, maxim, m, j;

int main() {
	ifstream f("flip.in");
	ofstream g("flip.out");
	f>>n>>m;
	for (i=1;i<=n;i++)
		for (j=1;j<=m;j++)
			f>>a[i][j];
	f.close();
	
	while (v[0] == 0) {
		i = m;
		while (v[i] == 1) {
			v[i] = 0;
			i--;
		}
		v[i] = 1;
		
		for (i=1;i<=n;i++)
			for (j=1;j<=m;j++)
				b[i][j] = a[i][j];
		
		for (i=1;i<=m;i++) {
			if (v[i] == 1) {
				for (j=1;j<=n;j++)
					b[j][i] = -b[j][i];
			}
		}
		
		sc = 0;
		for (i=1;i<=n;i++) {
			s = 0;
			for (j=1;j<=m;j++)
				s+=b[i][j];
			
			if (s > 0)
				sc += s;
			else
				sc -= s;				
			}
		
		
		if (sc > maxim)
			maxim = sc;
		
	}
	g<<maxim;
	g.close();
	return 0;
}