/*
task:ots
lang:c++
*/
#include<iostream>
#include<vector>
using namespace std;
int main()
{
   long n,i,p=0,c;
   vector <long> a;
   cin>>n;
   for(i=0;i<n;i++){cin>>c;a.push_back(c);}
   sort(a.begin(),a.end());
   p+=(a[1]-a[0]);
   p+=(a[n-1]-a[n-2]);
   if(n==2){cout<<a[1]-a[0]<<"\n";
           return 0;}                         
   if(n>3){
           for(i=1;i<n-3;i++){
                              if((a[i+1]-a[i])<(a[i+2]-a[i+1])){p+=a[i+1]-a[i];}
                              else if((a[i+1]-a[i])==(a[i+2]-a[i+1])){p+=a[i+1]-a[i];
                                                                      if((i<n-3)&&((a[i+3]-a[i+2])==(a[i+1]-a[i])))i++;
                                                                     }
                              else {p+=a[i+2]-a[i+1];i++;}
                              }}
    cout<<p<<"\n";                                                                                         
    return 0;
}
