HDU 1008

#include <bits/stdc++.h>
using namespace std;
#define test int t; cin>>t; while (t--)
#define ll long long int
#define fellow_junior  ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
int main()
{
   fellow_junior
   ll a,c,d,e,f,i,j,k,l;
   while(cin>>a && a)
   {
       c=a*5;
       d=0;
       for(i=0;i<a;i++)
       {
           cin>>e;
           if(e>d) c+=(e-d)*6;
           else c+=(d-e)*4;
           d=e;
       }
       cout<<c<<endl;
   }


   return 0;
}