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);
		if (n <= 3) {
		    System.out.println(arr[n - 1] - arr[0]);
		    return;
		}
		long[] dp = new long[n];
		dp[0] = Long.MAX_VALUE / 10;
		dp[1] = arr[1] - arr[0];
		dp[2] = arr[2] - arr[0];
		for (int i = 3; i < n; i++) {
		    dp[i] = Math.min(dp[i - 2] + arr[i] - arr[i - 1], dp[i - 3] + arr[i] - arr[i - 2]);
		}
		System.out.println(dp[n - 1]);
	}
}