#include<cstdio>
int m,n;
long a[17][17];
int main()
{FILE *f,*g;
 int i,j,sl[18];
 long sum,maxim=0;
 f=fopen("flip.in","r");
 fscanf(f,"%d%d",&n,&m);
 for(i=1;i<=n;++i)
 for(j=1;j<=m;++j)
 fscanf(f,"%ld",&a[i][j]);
 for(i=1;i<=n;++i)
 {sum=0;
  for(j=1;j<=m;++j)
   sum+=a[i][j];
  if(sum<0) sl[i]=-1;
  else sl[i]=1;
  maxim+=sum*sl[i];
  }
 for(j=1;j<=m;++j)
  {sum=maxim;
   for(i=1;i<=n;++i)
    sum=sum-2*a[i][j]*sl[i];
   if(sum>maxim) maxim=sum; 
   }
 fclose(f);
  g=fopen("flip.out","w");
  fprintf(g,"%d",maxim);
  fclose(g);
  return 0;
}