#include<bits/stdc++.h>
using namespace std;
#ifdef LOCAL_DEBUG
  #include "LOCAL_DEBUG.hpp"
#endif
#define int long long
const int INF = 1LL << 60;

signed main(){

  int n; cin >> n;
  vector<int> a(n);
  for(int i = 0; i < n; i++){
    cin >> a[i];
  }
  sort(a.begin(),a.end());

  vector<int> dp(n+1, INF);
  dp[0] = 0;
  dp[1] = a[1] - a[0];
  if(n > 2) dp[2] = a[1] - a[0] + a[2] - a[1];
  for(int i = 2; i < n; i++){
    if(i-2 > 0) dp[i] = min(dp[i], dp[i-2] + a[i] - a[i-1]);
    if(i-3 > 0) dp[i] = min(dp[i], dp[i-3] + a[i] - a[i-2]);
  }
  cout << dp[n-1] << endl;

  return 0;
}