#include <bits/stdc++.h>
using namespace std;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    vector<int> a(n);
    for(auto &&v : a) cin >> v;
    sort(a.begin(), a.end());
    vector<long> dp(n + 1, 1ll << 60);
    dp[0] = 0;
    for(int i = 0; i + 2 <= n; i++){
        dp[i + 2] = min(dp[i + 2], dp[i] + a[i + 1] - a[i]);
        if(i + 3 <= n) dp[i + 3] = min(dp[i + 3], dp[i] + a[i + 2] - a[i]);
    }
    cout << dp[n] << '\n';
}