#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; 
}