/*
TASK:ots
LANG:C++
*/
#include <iostream>
int n,tmp;
int br,sum=0;
long int a[1000000],b[1000000];
using namespace std;
int sort1(long int,int);
int sort1(long int a[1000000],int n)
{
    for (int i=0;i<n;i++)
    {
        for (int j=0;j<n-1;j++)
        {
            if (a[j]>a[j+1])
            {
                tmp=a[j];
                a[j]=a[j+1];
                a[j+1]=tmp; 
            }
            
        } 
    }
}
int main()
{

    cin >> n;
    for (int q=0;q<n;q++)
    cin >> a[q];
    br=n/2+n%2;
    sort1(a,n);
    for (int w=0;w<n-1;w++)
    b[w]=a[w+1]-a[w];
    sort1(b,n-1);
    for (int t=0;t<br;t++)
    sum+=b[t];
    cout << sum;
    cout << endl;
return 0;
}
