#include <stdio.h>

int main()
{
	int n,m,i,j,l=0,c,ok=1;
	int a[16][16],ml=0,mc=0,sc,sl,sli,sci;
	long long suma=0;
	FILE* f=fopen("flip.in","rt");
	FILE* g=fopen("flip.out","wt");

	fscanf(f,"%d%d", &n,&m);

	for (i=1;i<=n;i++)
	{
		for (j=1;j<=m;j++)
		{
			fscanf(f,"%d", &a[i][j]);
		}
	}
	// linii -->
	for (i=1;i<=n;i++)
	{
		sl=0;
		sli=0;
		for (j=1;j<=m;j++)
		{
			if (ok)
			{
				sl+=a[i][j];
				sli+=(a[i][j]*(-1));
			}
			else
				a[i][j]*=(-1);
		}
		if (sl<sli)
		{
			i--;
			ok=0;
		}
		else ok=1;
	} // <-- linii
	// coloane -->
	for (i=1;i<=m;i++)
	{
		sc=0;
		sci=0;
		for (j=1;j<=n;j++)
		{
			if (ok)
			{
				sc+=a[j][i];
				sci+=(a[j][i]*(-1));
			}
			else 
				a[j][i]*=(-1);
		}
		if (sci>sc)
		{
			i--;
			ok=0;
		}
		else
			ok=1;
	}

	for (i=1;i<=n;i++)
		for(j=1;j<=m;j++)
			suma+=a[i][j];

	fprintf(g,"%d",suma);

	fclose(f);
	fclose(g);
	
	return 0;
}