#include<stdio.h>
int n,m,v[17][17];
int sum1,sum2;
int matrice()
{
	int sumai=0;
	for(int i=1;i<=n;++i)
		for(int j=1;j<=m;++j)
		{
			scanf("%d",&v[i][j]);
			sumai+=v[i][j];
		}
	return sumai;
}
void intorc()
{
	for(int p=1;p<=n;++p)
		for(int t=1;t<=m;++t)
			v[p][t]=v[p][t]*(-1);
}
int verific()
{
	int sumad=0,j=0;
	for(int i=1;i<=n;++i)
	{
		for(j=1;j<=m;++j)
			sum1+=v[i][j];
		if(sum1<0)
		{
			for(int p=j;p<=m;++p)
			{
				v[i][p]*=(-1);
				sumad+=v[i][p];
			}
		}
		else sumad+=sum1;
	}
	return sumad;
}
int main()
{
	int a,b;
	freopen("flip.in","r",stdin);
	freopen("flip.out","w",stdout);
	scanf("%d%d",&n,&m);
	matrice();
	intorc();
	verific();
	a=matrice();
	b=verific();
	if(a>b)
		printf("%d",a);
	else printf("%d",b);
	return 0;
}