#include <fstream.h>
ifstream f("flip.in");
ofstream g("flip.out");
int main()
{
	int n,m,i,j,v[100][100],s,s2,s3,s4,sadevarat=0,a,b;

  f>>n>>m;
  for(i=1;i<=n;i++)
  for(j=1;j<=m;j++) f>>v[i][j];

  for(i=1;i<=n;i++)
	{s=0;s2=0;b=i;
		for(j=1;j<=m;j++)
			{ s+=v[i][j];
			 s2-=v[i][j];
			 } if(s<s2)
				{ for(i=b;i<b+1;i++)
				  for(j=1;j<=m;j++) v[i][j]=(-1)*v[i][j];
				 }
	 }
  for(j=1;j<=m;j++)
	 { s3=0;s4=0;a=j;
		for(i=1;i<=n;i++)
			{ s3+=v[i][j];
			 s4-=v[i][j];
			 } if(s3<s4)
				{ for(j=a;j<a+1;j++)
				  for(i=1;i<=n;i++) v[i][j]=(-1)*v[i][j];
				}
	  }
 for(i=1;i<=n;i++)
 for(j=1;j<=m;j++) sadevarat+=v[i][j];
 g<<sadevarat<<"\n";
 return 0;
 }