#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

int main() {
    int n;
    cin >> n;
    ll a[n];
    rep(i,n) cin >> a[i];
    sort(a,a+n);
    ll dp[n+1] = {};
    ll INF = 1001001001001001001;
    rep(i,n+1)dp[i] = INF;
    dp[0] = 0;
    srep(i,2,n+1){
        dp[i] = dp[i-2] + a[i-1] - a[i-2];
        if(i >= 3){
            dp[i] = min(dp[i], dp[i-3]+a[i-1]-a[i-3]);
        }
    }
    cout << dp[n] << endl;
    return 0;
}