/*
TASK:ots
LANG:C++
*/

#include<iostream>
using namespace std;
int main()
{
    int n,a[100000],i;
    long sum=0;
    scanf("%d",&n);
    for(i=0;i<n;i++)
       scanf("%d",&a[i]);
    sort(a,a+n);
    for(i=1;i<n;i++)
      a[i-1]=a[i]-a[i-1];
    for(i=0;i<=n-3;i++)
    {
     if(a[i]>a[i+1]){a[i]=0;i++;}
     if(a[i]<a[i+1]&&a[i]+a[i+1]<a[i+2]){a[i+2]=0;i+=2;}
     if(a[i]==a[i+1]&&i+2<=n-2){a[i+1]=0;i++;}
    }
    for(i=0;i<n-1;i++)
      sum+=a[i];
    cout<<sum<<'\n';
    return 0;
}
