#include <stdio.h>
#include <limits.h>
FILE *f,*g;
int n,m,a[17][17],x[17],viz[17];
int smax=INT_MIN;

void subm()
{int i,j;
 int s=0,sum=0;
 for(i=1;i<=n;i++)
 {s=0;
  for(j=1;j<=m;j++)
  {if(viz[j]==1)
     s=s-a[i][j];
   else
 	 s+=a[i][j];  
  }	  
  if(s>0)
	  sum+=s;
  else
	  sum-=s;
 }
 if(sum>smax)
	 smax=sum;
}

void back(int k)
{int i;
 for(i=x[k-1]+1;i<=m;i++)
 {x[k]=i;
  viz[i]=1;
  subm();
  if(k<m)
	  back(k+1);
  viz[i]=0;
 }
 
}

int main()
{int i,j;
 f=fopen("flip.in","r");
 g=fopen("flip.out","w");
 
 fscanf(f,"%d %d",&n,&m);
 for(i=1;i<=n;i++)
    for(j=1;j<=m;j++)
		fscanf(f,"%d",&a[i][j]);

 fclose(f);

 back(1); 
 fprintf(g,"%d",smax);
 fclose(g);
return 0;
}