//#include<fstream.h>
//#include<math.h>
#include<fstream>
#include<math>
int main()
{
  long n,m,i,j,k,a[17][17],x[17]={0},s,s2,smax=0;
  ifstream f("flip.in");ofstream g("flip.out");
  f>>n>>m;
  for(i=1;i<=n;i++)
    for(j=1;j<=m;j++){f>>a[i][j];smax+=a[i][j];}
  k=1;x[k]=0;
  while(k)
  {
    while(x[k]<2)
    {
      x[k]++;
      if(k==n)
      {
	s=0;
	for(j=1;j<=m;j++)
	{
	  s2=0;
	  for(i=1;i<=n;i++)
	    if(x[i]==1)s2-=a[i][j];
	    else s2+=a[i][j];
	  s+=abs(s2);
	}
      if(s>smax)smax=s;
      }
      else x[++k]=0;
    }
    x[k--]=0;
  }
  g<<smax;
  f.close();g.close();
  return 0;
}