import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
        }
        Arrays.sort(arr);
        long[][] dp = new long[n][2];
        dp[0][1] = 0;
        dp[0][0] = Long.MAX_VALUE / 10;
        dp[1][0] = arr[1] - arr[0];
        dp[1][1] = Long.MAX_VALUE / 10;
        for (int i = 2; i < n; i++) {
            dp[i][0] = Math.min(dp[i - 1][1] + arr[i] - arr[i - 1], dp[i - 2][1] + arr[i] - arr[i - 2]);
            dp[i][1] = dp[i - 1][0];
        }
        System.out.println(dp[n - 1][0]);
    }
}