#include <stdio.h>
#include <math.h>
#include <stdlib.h>

int max=0,k,v[17][17],u[17],n,m;

void suma()
{
	int i,j,s,s2;
	s2=0;
	for (j=1;j<m+1;j++)
	{
		s=0;
		for (i=1;i<n+1;i++) s+=(u[i]+1)*v[i][j];
		s2+=abs(s);
	}
	if (s2>max) max=s2;
}

void back()
{
	--k;
	int i;
	if (k==0) for (i=1;i<n+1;i++) if (u[i]==0) {u[i]=-2;suma();u[i]=0;}
	else for (i=1;i<n+1;i++) if (u[i]==0) {u[i]=-2;back();u[i]=0;}
	++k;
}

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