#include<stdio.h>

main ()
{
	int n, m, a[15][15], i, j, s=0, s1=0, s2=0;
	FILE *f;
	
f = fopen("flip.in", "r");
	fscanf(f, "%d %d", &n, &m);
	for(i=0; i<n; i++)
		for(j=0; j<m; j++)
			fscanf(f, "%d", &a[i][j]);
fclose(f);

	for(i=0; i<n; i++)
	{
		s1 = s2 = 0;
		
		for(j=0; j<m; j++)
		{
			s1+= a[i][j];
			s2-= a[i][j];
		}		

	if(s1<s2)
		for(j=0; j<m; j++)
			a[i][j]= -a[i][j];
	}
	
	for(i=0; i<m; i++)
	{
		s1 = s2 =0;
		
		for(j=0; j<n; j++)
		{
			s1+= a[j][i];
			s2-= a[j][i];			
		}

	if(s1<s2)
		for(j=0; j<n; j++)
			a[j][i]= -a[j][i];		
	}
	
	for(i=0; i<n; i++)
		for(j=0; j<m; j++)
			s+= a[i][j];
			
f = fopen("flip.out", "w+");
	fprintf(f, "%d", s);
fclose(f);	
}