#include <iostream>
#include <fstream>
#include <math.h>
using namespace std ;
int main ()
{
 long int mat[16][16];
 unsigned int l , r ,  n , m , Spoz= 0 , i , Stotal = 0  ;  
 int Sneg = 0 ; 
 fstream f("flip.in",ios::in );
 f >> m ; f >> n ; 
 for( r = 0 ; r < m ; r++)
 {
  for( l = 0 ; l < n ; l++ )
  {
   f >> mat [r] [l] ;
   if( mat[r][l] > 0 )
    Spoz += mat [ r ] [ l ];
   else
    Sneg += mat[ r ] [ l ];    
  }//primu for
  if( abs(Sneg) > Spoz )
  {
   for( i = 0 ; i < n ; i ++ )
   mat[ r ] [ i ] *= -1;
  } 
  Sneg = 0 ; Spoz = 0 ;
 }//al 2-lea for 
 for( l = 0 ; l < n ; l++ )
 {
  for( r = 0 ; r < m ; r++ )
  {
   if ( mat [ r ] [ l ] < 0 )
    Sneg += mat [ r ] [ l ] ;
   else 
    Spoz += mat [ r ] [ l ] ; 
  }
  if( abs( Sneg ) > Spoz )
   Stotal +=abs(Sneg) - Spoz ;
  else 
   Stotal += Spoz -abs(Sneg);
   Spoz = 0 ;
   Sneg = 0 ;  
 }
 fstream g("flip.out",ios::out);
 g<<Stotal;
 return 0 ; 
}