#include <stdio.h>
FILE *f,*g;
int n,m,i,j;
long max=0;
long 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++)
  if (sol2[i]==0) sol2[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 back2(int k){
 int i;
 if (k<=m)
  for (i=-1;i<=0;i++){
   sol2[k]=i;
   ok(k);
   back2(k+1);
  }
}
void back1(int k){
 int i;
 if (k<=n)
  for (i=-1;i<=0;i++){
   sol1[k]=i;
   back2(1);
   back1(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]);
 back1(1);
 fprintf(g,"%ld\n",max);
 fclose(f);
 fclose(g);
 return 0;
}