import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        long[] values = new long[n];
        for (int i = 0; i < n; i++) {
            values[i] = sc.nextInt();
        }
        Arrays.sort(values);
        if (n == 2) {
            System.out.println(values[1] - values[0]);
            return;
        }
        long[] dp = new long[n + 1];
        dp[0] = 0;
        dp[1] = Long.MAX_VALUE / 2;
        dp[2] = values[1] - values[0];
        dp[3] = values[2] - values[0];
        for (int i = 4; i <= n; i++) {
            dp[i] = Math.min(dp[i - 2] + values[i - 1] - values[i - 2], dp[i - 3] + values[i - 1] - values[i - 3]);
        }
        System.out.println(dp[n]);
    }
    
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String nextLine() throws Exception {
        return br.readLine();
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}