#include<stdio.h>

int n,m,a[17][17],b[17][17],smax,sp,sn,suma;
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;i++)
	{	
		for(j=1;j<=m;j++)
		{	
			scanf("%d",&a[i][j]);
			printf("%d ",a[i][j]);
			b[i][j]=a[i][j];
			smax+=b[i][j];
		}
	}	
/////
	for(j=1;j<=m;j++)
	{
		sp=0;
		sn=0;
		for(i=1;i<=n;i++)
		{
			if(b[i][j]>=0)
				sp+=b[i][j];
			else
				sn+=b[i][j];
		}	
		if(sn+sp>=0)
			suma+=sn+sp;
		if(-sn>sp)
		{
			suma+=-sn-sp;
			for(i=1;i<=n;i++)
				b[i][j]=-a[i][j];
		}	
		if(suma>smax)
			smax=suma;
	}
///////
	suma=0;
	for(i=1;i<=n;i++)
	{
		sp=0;
		sn=0;
		for(j=1;j<=m;j++)
		{
			if(b[i][j]>=0)
				sp+=b[i][j];
			else
				sn+=b[i][j];
		}	
		if(sn+sp>=0)
			suma+=sn+sp;
		if(-sn>sp)
		{
			suma+=-sn-sp;
			for(j=1;j<=m;j++)
				b[i][j]=-a[i][j];
		}	
		if(suma>smax)
			smax=suma;
	}	
	printf("%d\n",smax);
	return 0;
}