#include <fstream>
using namespace std;
int main()
{
	int n,m,i,j,s1=0,s2=0,a[10000][10000],suma=0;
	fstream f("flip.in");
	ofstream o("flip.out");
	f>>n>>m;
	for(i=0;i<n;i++)
		for(j=0;j<m;j++)
			f>>a[i][j];
	for (i=0;i<n;i++)
	{
		for (j=0;j<m;j++)
		{
			s1=s1+a[i][j];
			s2=s2+(a[i][j]*(-1));
		}
	if (s2>s1)
	suma = suma + s2;
	else
	suma = suma + s1;
	s1=0; s2=0;
	};
	o<<suma;
	return 0;
}