#include<stdio.h>  
int n,i,j,k,v[20*20],a[20][20],b[20][20],x,z,suma,max,m,y;  
int main() {  
FILE*f=fopen("flip.in","r");  
FILE*g=fopen("flip.out","w");  
max=-4000;  
fscanf(f,"%d %d",&n,&m);  
for(i=1;i<=n;i++)  
for(j=1;j<=m;j++)  
fscanf(f,"%d",&a[i][j]);  
while(v[0]!=1) {   
k=m;   
while(v[k]==1)        
v[k--]=0;        
v[k]=1;   
for(i=1;i<=n;i++)  
for(j=1;j<=m;j++)  
b[i][j]=a[i][j];  
for(i=1;i<=m;i++)              
if(v[i]==1)  
for(j=1;j<=n;j++)  
b[j][i]=-a[j][i];  
suma=0;  
for(i=1;i<=n;i++){  
x=0;  
for(j=1;j<=m;j++)  
x+=b[i][j];  
if(x>0)  
suma+=x;  
else
suma+=-x;  
}  
if(suma>max)  
max=suma; 
}  
fprintf(g,"%d",max); 
fclose(f);  
fclose(g);  
return 0;  
}