#include <fstream>
#define DIM 20

int v[DIM];
int a[DIM][DIM], b[DIM][DIM];
int i,n,j,sum,maxim,s,m;

using namespace std;

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];
	
	
	for (;;) {
		
		for (i=1;i<=n;i++)
			for (j=1;j<=m;j++)
				b[i][j] = a[i][j];
		
		i = m;
		while (v[i] == 1) {
			v[i] = 0;
			i--;
		}
		v[i] = 1;
		
		
		
		for (i=1;i<=m;i++)
			if (v[i] == 1) {
				for (j=1;j<=n;j++)
					b[j][i]*=(-1);
				//intorc coloana i din b
			}
			
		sum = 0;
		for (i=1;i<=n;i++) {
			s = 0;
			for (j=1;j<=m;j++)
				s += b[i][j];
			if (s > 0)
				sum += s;
			else
				sum -=s;
		}
		
		
		if (sum > maxim)
			maxim = sum;
		
		
		if (v[0] == 1)
			break;
		
	}
	
	g<<maxim;
	return 0;
}