#include<bits/stdc++.h>
using namespace std;
using Int = long long;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}

//INSERT ABOVE HERE
signed main(){
  Int n;
  cin>>n;
  vector<Int> ys(n);
  for(Int i=0;i<n;i++) cin>>ys[i];
  sort(ys.begin(),ys.end());
  const Int INF = 1e15;
  vector<Int> dp(n,INF);
  dp[1]=ys[1]-ys[0];
  dp[2]=ys[2]-ys[0];
  for(Int i=1;i<n;i++){
    if(i+2<n) chmin(dp[i+2],dp[i]+ys[i+2]-ys[i+1]);
    if(i+3<n) chmin(dp[i+3],dp[i]+ys[i+3]-ys[i+1]);
  }
  cout<<dp[n-1]<<endl;
  return 0;
}