# include <stdio.h>
int i,j,a[100][100],n,m;
long s,s1,s2;
int main ()
{
freopen ("flip.in","r",stdin);
freopen ("flip.out","w",stdout);

scanf ("%i",&n);
scanf ("%i",&m);
for (i=0;i<n;i++)
for (j=0;j<m;j++)
scanf ("%i",&a[i][j]);
for (i=0;i<n;i++)
{
s1=0;
s2=0;
for (j=0;j<m;j++)
s1=s1+a[i][j];
for (j=0;j<m;j++)
s2=s2+(a[i][j]*-1);
if (s1<s2)
for (j=0;j<m;j++)
a[i][j]=a[i][j]*-1;
}
for (j=0;j<m;j++)
{
s1=0;
s2=0;
for (i=0;i<n;i++)
s1=s1+a[i][j];
for (i=0;i<n;i++)
s2=s2+(a[i][j]*-1);
if (s1<s2)
for (i=0;i<n;i++)
a[i][j]=a[i][j]*-1;
}
for (i=0;i<n;i++)
for (j=0;j<m;j++)
s=s+a[i][j];
printf ("%ld",s);
return 0;
}