#include <stdio.h>  
FILE *f=fopen("flip.in","r");
FILE *g=fopen("flip.out","w");
long a[16][16],b[16],s1,s2,max;
int x,y,i,j,p;
int main()
{  
fscanf(f,"%d %d",&x,&y);
for(i=0;i<x;i++)  
    for(j=0;j<y;j++)  fscanf(f,"%ld",&a[i][j]);  
while(p>=0) {  if(b[p]==1) { b[p]=0;  
                             p--;  
                             continue;  
                            }  
                else if(b[p]==-1) b[p]=1;  
                     else b[p]=-1;  
                if(p==y) { s1=0;  
                           for(i=0;i<x;i++) { s2=0;  
                                              for(j=0;j<y;j++)  s2+=b[j]*a[i][j];  
                                              if(s2<0)  s1-=s2;  
                                              else s1+=s2;
                                             }

                           if(s1>max) max=s1; 
                           continue;  
			  }
                 p++;  
             }  
fprintf(g,"%ld",max);  
return 0;  
}