#include <stdio.h>
FILE *f,*g;
int i,j;
long n,m,max=0;
long s,a[20][20],sol1[20],sol2[20];
void ok(int k){
 long s=0;
 int i,j;
 for (i=1;i<=n;i++)
  if (sol1[i]==0) sol1[i]=1;
 for (i=1;i<=n;i++)
  for (j=1;j<=m;j++)
   s+=sol1[i]*sol2[j]*a[i][j];
 if (s>max) max=s;
}
void back(int k){
 int i;
 if (k<=n)
  for (i=-1;i<=0;i++){
   sol1[k]=i;
   ok(1);
   back(k+1);
  }
}
int main(){
 f=fopen("flip.in","r");
 g=fopen("flip.out","w");
 fscanf(f,"%ld%ld",&n,&m);
 for (i=1;i<=n;i++)
  for (j=1;j<=m;j++)
   fscanf(f,"%ld",&a[i][j]);
 s=0;
 for (j=1;j<=m;j++){
  for (i=1;i<=n;i++)
   s+=a[i][j];
  if (s<s*-1) sol2[j]=-1;
   else sol2[j]=1;
  s=0;
 }
 back(1);
 fprintf(g,"%ld\n",max);
 fclose(f);
 fclose(g);
 return 0;
}