#include <stdio.h>

using namespace std;

FILE *f=fopen("flip.in","r");
FILE *g=fopen("flip.out","w");



int n,m,a[17][17],x[50],max,nn,i,j,b[17][17];

void afis(int r)
{
  int i,s=0,s1=0,j;
  for(i=1;i<=n;i++)
  for(j=1;j<=m;j++)
   b[i][j]=a[i][j];
 for(i=1;i<=r;i++)
  {
   if (x[i]==1)
    for(j=1;j<=m;j++)
     b[i][j]*=-1;
  }
 for(j=1;j<=m;j++)
 {
     s1=0;
  for(i=1;i<=n;i++)
  s1+=b[i][j];
 if (s1<0)s+=-s1;
 else s+=s1;
 }
if (s>max)max=s;
}


void back(int k)
{
  int i;
  for(i=0;i<=1;i++)
  {
   x[k]=i;
   if(k==nn)afis(n);
   else back(k+1);
  }
}


int main()
{
  max=0;
  fscanf(f,"%d %d",&n,&m);
  for(i=1;i<=n;i++)
  for(j=1;j<=m;j++)
  fscanf(f,"%d",&a[i][j]);
  nn=n;
  back(1);
  fprintf(g,"%d",max);
  fclose(g);
  return 0;
}