n = int(input())
Y = list(map(int, input().split()))

Y.sort()

if n == 2:
    print(Y[1]-Y[0])
    exit()

if n == 3:
    print(Y[2]-Y[0])
    exit()

INF = 10**18
dp = [INF]*n
dp[1] = Y[1]-Y[0]
dp[2] = Y[2]-Y[0]
for i in range(3, n):
    dp[i] = min(dp[i-3]+Y[i]-Y[i-2], dp[i-2]+Y[i]-Y[i-1])
print(dp[n-1])