#include<stdio.h>
using namespace std;
int v[17][17],n,m;
int sm = 0;
	FILE *f=fopen("flip.in","r"), *g=fopen("flip.out","w"); 
void citire()
{
	fscanf(f,"%d%d",&n,&m);
	for (int i=1;i<=n;++i)
		for (int j=1;j<=m;++j)
			fscanf(f,"%d",&v[i][j]);
}

void c()
{
	int s,st=0;
	for (int j=1;j<=m;++j)
	{
		s=0;
		for (int i=1;i<=n;++i)
			s+=v[i][j];
		if (s>0)
			st+=s;
		else
			st-=s;
	}
	if (st>sm)
		sm=st;
}

void b(int i)
{
	if (i>n)
		return;
	c();
	b(i+1);
		for (int j=1; j<=m;++j)
			v[i][j]=-v[i][j];
	c();
	b(i+1);
	return;
}

int main()
{

	citire();
	b(1);
	fprintf(g,"%d",sm);
	
fclose(f);
fclose(g);
	return 0;
}