import sys
input = sys.stdin.readline

N=int(input())
Y=list(map(int,input().split()))
Y.sort()

DP=[float("inf")]*N


DP[1]=Y[1]-Y[0]
DP[2]=Y[2]-Y[0]
DP[3]=Y[1]-Y[0]+Y[3]-Y[2]

for i in range(4,N):
    DP[i]=min(DP[i-2]+Y[i]-Y[i-1],DP[i-3]+Y[i]-Y[i-2])

print(DP[N-1])