#include <stdio.h>
int v[17][17],n,m;
int sm = 0;

void citire()
{
	scanf("%d%d",&n,&m);
	for (int i=1;i<=n;++i)
		for (int j=1;j<=m;++j)
			scanf("%d",&v[i][j]);
}

void c()
{
	int s,st=0;
	for (int j=1;j<=m;++j)
	{
		s=0;
		for (int i=1;i<=n;++i)
			s+=v[i][j];
		if (s>0)
			st+=s;
		else
			st-=s;
	}
	if (st>sm)
		sm=st;
}

void b(int i)
{
	if (i>n)
		return;
	c();
	b(i+1);
		for (int j=1; j<=m;++j)
			v[i][j]=-v[i][j];
	c();
	b(i+1);
}

int main()
{
	freopen("flip.in","r",stdin);
	freopen("flip.out","w",stdout);
	citire();
	b(1);
	printf("%d",sm);
	return 0;
}