1020:电梯升降

#include <iostream>
using namespace std;
int main()
{
int sum,a,s,n,N;
while (cin>>n)
{
sum=0;
a=0;
if(n==0)
break;
N=n;
while(n>0)
{
cin>>s;
if(a<s)
sum=(s-a)*6+sum;
else
sum=(a-s)*4+sum;
a=s;
n--;
}
cout<<sum+5*N<<endl;
}
return 0;
}