def diff2(a,b):
    return abs(a-b)

def diff3(a,b,c):
    s = abs(a-b) + abs(b-c) + abs(a-c)
    return s//2

N = int(input())

a = list(map(int,input().split()))
a.sort()

INF = float("inf")
dp = [INF] * (N+1)
dp[0] = 0

for i in range(N):

    if i+2 < len(dp):
        dp[i+2] = min(dp[i+2] , dp[i] + diff2(a[i],a[i+1]) )
    if i+3 < len(dp):
        dp[i+3] = min(dp[i+3] , dp[i] + diff3(a[i],a[i+1],a[i+2]) )

# print (dp)
print (dp[-1])