n = int(input())
*a, = map(int,input().split())
a.sort()
INF = 10**18
dp = [INF]*n
dp[1] = a[1] - a[0]
for i in range(2,n):
    dp[i] = min(dp[i-2] + a[i] - a[i-1], (dp[i-3] if i >= 3 else 0) + a[i] - a[i-2])
print(dp[-1])