#include <stdio.h>
int n,m,max=0;
int mat[17][17];
bool col[17],lin[17];

void back(int);
void back2(int);
int suma();

int main ()
{
	freopen ("flip.in","r",stdin);
	freopen ("flip.out","w",stdout);
	scanf ("%d%d",&n,&m);
	for (int i=1;i<=n;++i)
		for (int j=1;j<=m;++j)
			scanf ("%d",&mat[i][j]);
	back(1);
	printf ("%d",max);
	return 0;
}

void back(int p)
{
	if (p>m)
	{
		back2(1);
		return;
	}
	col[p]=0;
	back(p+1);
	col[p]=1;
	back(p+1);
}

void back2(int p)
{
	if (p>n)
	{
		int x=suma();
		if (x>max)
			max=x;
		return;
	}
	lin[p]=0;
	back2(p+1);
	lin[p]=1;
	back2(p+1);
}

int suma()
{
	int s=0;
	for (int i=1;i<=n;++i)
		for (int j=1;j<=m;++j)
			s+=mat[i][j]*(col[j]*2-1)*(lin[i]*2-1);
	return s;
}