#include <bits/stdc++.h>

using namespace std;

using ll = long long;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    vector<ll> y(n);
    for (int i = 0; i < n; i++) cin >> y[i];
    sort(y.begin(), y.end());

    vector<ll> dp(n + 1, 1e18);
    dp[0] = 0;
    for (int i = 1; i < n; i++) {
        dp[i + 1] = min(dp[i + 1], dp[i - 1] + y[i] - y[i - 1]);
        if (i > 1) dp[i + 1] = min(dp[i + 1], dp[i - 2] + y[i] - y[i - 2]);
    }
    cout << dp[n] << endl;
    return 0;
}