#include <stdio.h>
int n,m;
long x[17][17];
long long a[17],b[17];
long long l;
int main()
 {
  freopen ("flip.in","r",stdin);
  freopen ("flip.out","w",stdout);
  scanf("%d %d",&n,&m);
  int i,j;
  for (i=1;i<=n;i++)
   for (j=1;j<=m;j++)
    {
     scanf("%ld ",&x[i][j]);
     a[i]+=x[i][j];
     b[j]+=x[i][j];
    }
 for (i=1;i<=n;i++)
    if (a[i]<0)
      {
       a[i]*=-1;
       for (j=1;j<=m;j++)
	{
	 b[j]-=(2*x[i][j]);
	 x[i][j]*=-1;
	}
      }
 for (i=1;i<=m;i++)
    if (b[i]<0)
      {
       b[i]*=-1;
       for (j=1;j<=n;j++)
	{
	 a[j]-=(2*x[i][j]);
	 x[i][j]*=-1;
	}
      }
 for (i=1;i<=n;i++)
    {
     l+=a[i];
    }
 printf("%lld",l);
 return 0;
}