n = int(input())
a = [int(i) for i in input().split()]
a.sort()
dp = [0] * n
dp[1] = a[1] - a[0]

if n > 2:
    dp[2] = a[2] - a[0]
    for i in range(3, n):
        dp[i] = min(dp[i - 2], dp[i - 1]) + a[i] - a[i - 1]

print(dp[-1])