#include<iostream>
#include<fstream>
using namespace std;
int maxim,n,m,a[17][17],i,j,c,l,s;
ifstream f("flip.in");
ofstream g("flip.out");
void citire()
{

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

}
void suma()
{
	for(i=1;i<=n;i++)
		for(j=1;j<=n;j++)
			s+=a[i][j];
}
void lini()
{
	for(i=1;i<=m;i++)
		a[l][i]*=-1;
}
void coloane()
{
	for(i=1;i<=n;i++)
		a[i][c]*=-1;
}
int main()
{

	citire();
	s=0;
	suma();
	maxim=s;
	c=1;
	l=1;
	while(l<=n)
	{
		lini();
		c=1;
		while(c<=m)
		{
			s=0;
			coloane();
			suma();
			if(s>maxim)
				maxim=s;
			coloane();
			c++;
		}
		lini();
		l++;
	}

	g<<maxim;

	return 0;
}