#include<iostream>
#include<fstream>
#include<cstdlib>
#include<algorithm>
#include<limits>

using namespace std;

#define MAX_N 10000
#define ERROR -1

int N;
int val[MAX_N];
int diff[MAX_N];
//int mem[MAX_N][MAX_N];

// solve(i,j) = min( diff[i]+solve(i+2,j-1), solve(i+1,j) )
int solve(int i, int j){
  
  if( j==0 ) return 0;
  if( i>=N-1 && j==0 ) return 0;
  if( i>=N-1 && j!=0 ) return ERROR;
  int prendi = solve(i+2,j-1);
  int lascia = solve(i+1,j);
  if( prendi==ERROR )
    return lascia;
  if( lascia==ERROR )
    return prendi+diff[i];
  return min( prendi+diff[i], lascia );
}

int main(int argc, char **argv){

  ifstream in("input.txt");
  in >> N;
  for(int i=0;i<N;i++)
    in >> val[i];
  in.close();

  // Inizializzo
  /*for(int i=0;i<N;i++)
    for(int j=0;j<N;j++)
      mem[i][j] = -1;*/

  // Li ordino
  sort( val,val+N	 );
  // Calcolo le differenze
  for(int i=0;i<N-1;i++)
    diff[i] = abs( val[i]-val[i+1] );
  // Risolvo
  int res = solve(0,N/3);

  ofstream out("output.txt");
  out << res << "\n";
  out.close();

  return 0;
}