#include <iostream>
#include <fstream>
#include <string.h>
using namespace std;

struct tab
{
	int t[256];
	short m;
	short n;
};

int put2 (short a)
{
	short n;
	for (n=1;a;a--)
		n=n*2;
	return n;
}

char val (short a)
{
	return a+'0';
}

char* bin (int n, int p2)
{
	char s1[16],r1[16];
	char *s,*r;
	s=s1;
	r=r1;
	strcpy(s,"");
	short i,l;
	for (i=0;n;n=n/2,i++)
		s[i]=val(n%2);
	s[i]='\0';
	for (;i<p2;i++)
		strcat(s,"0");
	l=i;
	s[l]='\0';
	strcpy(r,s);
	for (i=0;i!=l;i++)
		r[i]=s[l-i-1];
	r[l]='\0';
	return r;
}

tab flipl (tab a, short i)
{
	short j;
	for (j=0;j<a.m;j++)
		a.t[i*a.m+j]=-a.t[i*a.m+j];
	return a;
}

tab flipc (tab a, short i)
{
	short j;
	for (j=0;j<a.n;j++)
		a.t[j*a.m+i]=-a.t[j*a.m+i];
	return a;
}

int suma (tab a)
{
	int s=0;
	short i;
	for (i=0;i<a.m*a.n;i++)
		s=s+a.t[i];
	return s;
}

int sumac (tab a, char* s)
{
	short j;
	int S,max=0;
	tab b;
	for (j=0;j<a.n;j++)
		if (s[j]=='1')
			a=flipl(a,j);
	max=suma(a);
	for (j=0;j<a.m;j++)
		{
		b=flipc(a,j);
		S=suma(b);
		if (S>max)
			max=S;
		}
	return max;	
}

int comb (tab a)
{
	short i,p;
	int max=0,S;
	p=put2(a.n);
	for (i=0;i<p;i++)
		{
		S=sumac(a,bin(i,a.n));
		if (S>max)
			max=S;
		}
	return max;
}

int main ()
{
	fstream f("flip.in", ios::in);
	fstream g("flip.out", ios::out);
	short i,j;
	tab a;
	f>>a.n>>a.m;
	for (i=0;i<a.n;i++)
		for (j=0;j<a.m;j++)
			f>>a.t[i*a.m+j];
	g<<comb(a);
	g.close ();
}