#include<cstdio>
int a[20][20];
int n,m,i,j,pp=1,x=-1000000000,y,st[17];
void back(int k)
    {
    if(k==n+1)
        {
        int s=0;
        int i,j;
        for(i=1;i<=n;i++)
            if(st[i]==1)
                for(j=1;j<=m;j++)
                    a[i][j]*=-1;
        for(j=1;j<=m;j++)
            {
            int s1=0;
            for(i=1;i<=n;i++)
                s1=s1+a[i][j];
            if(s1<0)
                s1*=-1;
            s+=s1;
            }
        if(s>x)
            x=s;
        for(i=1;i<=n;i++)
            if(st[i]==1)
                for(j=1;j<=m;j++)
                    a[i][j]*=-1;
        }
    else
        {
        for(int i=0;i<=1;i++)
            {
            st[k]=i;
            back(k+1);
            }
        }
    }
int main ()
{
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]);
back(1);
printf("%d",x);
return 0;
}