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

int main() {
    int N;
    cin >> N;
    vector<long long> Y(N);
    for (int i = 0; i < N; i++) cin >> Y[i];
    sort(Y.begin(), Y.end());

    vector<long long> dp(N+1, 1LL << 60);
    dp[0] = 0;
    for (int i = 0; i < N; i++) {
        if (i+2 <= N) dp[i+2] = min(dp[i+2], dp[i] + Y[i+1] - Y[i]);
        if (i+3 <= N) dp[i+3] = min(dp[i+3], dp[i] + Y[i+2] - Y[i]);
    }

    cout << dp[N] << endl;
}