#include <iostream>
#include <fstream>

using namespace std;

int s,n,m;
long final,v[16][16];

void suma(int a, int b)
{
	int i,j;
	s=0;
	for(i=0;i<n;i++)
		for(j=0;j<m;j++)
		{
			if(i==a && j==b) s=s+v[i][j];
			else if(i==a) s = s + ( (-1)*v[i][j] );
			else if(j==b) s = s + ( (-1)*v[i][j] );
			else s=s+v[i][j];
		}
	//cout<<s<<endl;
	if(final<s) final=s;
}

int main()
{
	int i,j;
	ifstream f("flip.in");
	ofstream g("flip.out");
	f>>n>>m;
	for(i=0;i<n;i++)
		for(j=0;j<m;j++)
			f>>v[i][j];
	for(i=-1;i<n;i++)
		for(j=-1;j<m;j++)
			suma(i,j);
	f.close();
	g<<final;
	g.close();
	return 0;
}