/*
task:ots
lang:c++
*/
#include<iostream>
using namespace std;
 unsigned long long n, a[100], lenght[100];
int sort1(unsigned long long p[])
{
    for(unsigned long long int i=0;i<n;i++)
    {
		 for(unsigned long long int j=i+1;j<n;j++)
		 {
			      if(p[i]>p[j])
			      {
					   long long k=p[i];
					   p[i]=p[j];
					   p[j]=k;
			      }
		 }
    }
    return 1;
}

int main()
{

    cin>>n;
    unsigned long long i=0;
    for(i=0;i<n;i++)
    cin>>a[i];
    sort1(a);
    for(i=0;i<n-1;i++)
    lenght[i]=a[i+1]-a[i];
    unsigned long long used[100]={0}, sum=a[n-1]-a[0];
    for(i=1;i<n;i+=2)
    {
		 if(lenght[i]<(lenght[i-1]+lenght[i+1])/2)
		 sum=sum-lenght[i-1];
                 else sum=sum-lenght[i];

    }
    cout<<sum<<endl;
    return 0;
}
