#include<stdio.h>
#include<iostream.h>
int n,m,flip[16];
long matrice[16][16] ;
long long sumamax=0,suma,l;
void flipit()
{
	suma=0;
	int i,j;
	for(i=0;i<n;i++)
		{l=0;
			for(j=0;j<m;j++)
			 b+=matrice[i][j]*flip[i][0]*flip[j][1];
		if(l<0)	suma+= -b;
		else suma+=b;
	if(sumamax<suma)
		sumamax=suma;
}
void back()
{
	for(int j=0;j<m;j++)
	{	
		flip[j]=1;
		flipit();
		flip[j]=-1;
		flipit();
	}
}		
main()
{
	int i,j;
	freopen("flip.in","r",stdin);
	freopen("flip.out","w",stdout);
	cin>>n>>m;
		for(i=0;i<n;i++)
			for(j=0;j<m;j++)
				cin>>matrice[i][j];
	for(i=0;i<n;i++){flip[i][0]=1;flip[i][1]=1;}
	back();
	cout<<sumamax<<"\n";
}