include[HTML_REMOVED]
include[HTML_REMOVED]
using namespace std;
int main()
{
int n;
cin>>n;
int x[n],sum=0;
for(int i=0;i[HTML_REMOVED]>x[i];
sort(x,x+n);
for(int i=0;i<=n/2-1;i++)
{
sum+=(x[n-i-1]-x[i]);
}
cout<<sum;
}