n = int(input())
y = [int(i) for i in input().split()]

y.sort()
dp = [[[10**15]*2 for _ in range(3)] for _ in range(n)]

dp[0][1][0] = 0
dp[0][2][0] = y[1]-y[0]

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

print(min(dp[n-1][0][1],dp[n-1][1][1]))