#include <stdio.h>
#include <math.h>
#include <string.h>

int sc[17],v[17][17],m,n,sm,sct[17];

void invert(int k)
{
	int i=0,j=0;
	while (k)
	{
		if (k & 1)
		{
			for (j=0; j<m; j++)
				sc[j]-=2*v[i][j];
		}
		i++;
		k=k>>1;		
	}
	for (i=0; i<m; i++)
		if (sc[i]<0)
			sc[i]=-sc[i];
}

int sum()
{
	int i,s=0;
	for (i=0; i<m; i++)
		s+=sc[i];
	return s;
}

void serci()
{
	int p2,i,s;
	memmove(sct,sc,17);
	
	p2=(int)pow(2,n);
	for (i=0; i<=p2; i++)
	{
		invert(i);
		s=sum();
		if (s>sm)
			sm=s;
		memmove(sc,sct,17);
	}	
}


int main()
{
	int i,j;
	FILE *in=fopen("flip.in","r");
	fscanf(in,"%d%d",&n,&m);
	for (i=0; i<n; i++)
		for (j=0; j<m; j++)
		{
			fscanf(in,"%d",&v[i][j]);
			sc[j]+=v[i][j];
			sm+=v[i][j];
		}
	fclose(in);
	
	serci();
	
	FILE *out=fopen("flip.out","w");
	fprintf(out,"%d\n",sm);
	fclose(out);
	return 0;
}