#yuki838

n=int(raw_input())
y=map(int,raw_input().split())

y.sort()
dp=[0]*100001
if n==2:
 res=y[1]-y[0]
elif y==3:
 res=y[2]-y[0]
else:
 dp[0]=10**9
 dp[1]=y[1]-y[0]
 dp[2]=y[2]-y[0]
 for i in xrange(3,n):
  dp[i]=min(y[i]-y[i-2]+dp[i-3],y[i]-y[i-1]+dp[i-2])
 res=dp[n-1]
print res