#include<fstream>
using namespace std;
int matrice[17][17],coloana[17],linia[17];
int maxim=-10000000,n,m;
ifstream f1("flip.in");
ofstream f2("flip.out");
void afisare()
{int suma=0,i,d;
for(i=1;i<=n;i++)
	for(d=1;d<=n;d++)
		if(coloana[d]!=linia[i]) suma-=matrice[i][d];
		else suma+=matrice[i][d];
if(maxim<suma) maxim=suma;
}
void back(int i)
{if(i>n) 
{afisare();
return;
}
coloana[i]=0;
linia[i]=0;
back(i+1);

coloana[i]=0;
linia[i]=1;
back(i+1);

coloana[i]=1;
linia[i]=0;
back(i+1);

coloana[i]=1;
linia[i]=1;
back(i+1);

}

int main()
{int i,d;

f1>>n>>m;
for(i=1;i<=n;i++)
	for(d=1;d<=m;d++)
		f1>>matrice[i][d];
back(1);





f2<<maxim;





return 0;
}