#include <cassert>
#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
#define N 10000

#define ABS(x) ((x)>0) ? x : -(x);

int n;
int numeri[N];
int app[N];
int presi[N];
int n_triple;
int diff[N];

int scarto=50000;

void calcoladiff(){
	for(int i=1;i<=n;i++)
		diff[i]=ABS(numeri[i]-numeri[i+1]);
}

void ordina_prova(){
	int aux;
	for(int i=1;i<n;i++){
		for(int j=i+1;j<=n;j++){
			if(numeri[i]>numeri[j]){
				aux=numeri[j];
				numeri[j]=numeri[i];
				numeri[i]=aux;	
			}
		}
	}
}

int main() {

	ifstream fin("input.txt");
	fin >> n;
	//cout << "n " << n << endl;
	
	n_triple=n/3;
	
	for(int i=1;i<=n;i++)
		fin >> numeri[i];

	for(int i=1;i<=n;i++)
		presi[i]=2;
	/*
	for(int i=1;i<=n;i++)
		cout << "- " << numeri[i] << endl;
	*/

	ordina_prova();
	/*cout << "ordine:" << endl;
	for(int i=1;i<=n;i++)
		cout << ". " << numeri[i] << endl;
	*/
	
	//cout << endl <<"numeri: " << n << ", n_triplette: " << n_triple << endl;
	

	calcoladiff();
	/*for(int i=1;i<n;i++)
		cout << "diff: " << diff[i] << endl;
	*/

	int counter=40000;
	for(int i=1;i<n;i++){
		if(diff[i]<counter)
			counter=diff[i];	
	}
	//cout<< "counter: " << counter<< endl;

	int triple=0;
	int costo=0;
	while(triple<n_triple){
		for(int i=1;i<=n;i++){
		//cout << "i: " << i <<endl;
			if(diff[i]==counter && presi[i]==2 && presi[i+1]==2){
				//numeri[i]=numeri[i+1]=scarto;
				presi[i]=presi[i+1]=1;
				costo=costo+diff[i];
				triple=triple+1;
				//calcoladiff();
			}
		}
		counter=counter+1;
	}

	//cout << "costo: " << costo << endl;

	ofstream fout("output.txt");
	fout << costo;
return (0);}