#include <iostream>
#include <vector>
#include <algorithm>

using lint = long long;
constexpr lint INF = 1LL << 60;

void solve() {
    int n;
    std::cin >> n;

    std::vector<lint> xs(n);
    for (auto& x : xs) std::cin >> x;
    std::sort(xs.begin(), xs.end());

    std::vector<lint> dp(n + 1, INF);
    dp[0] = 0;
    for (int i = 2; i < n; ++i) {
        for (int k = 1; k <= 2; ++k) {
            lint cost = xs[i] - xs[i - k];
            dp[i + 1] = std::min(dp[i + 1], dp[i - k] + cost);
        }
    }

    std::cout << dp[n] << "\n";
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}