#include <iostream>
#include "cstring"
#include <stdio.h>
#include "iomanip"
#include "vector"
#include "cmath"
#include "stack"
#include "algorithm"
#include <math.h>
#include "map"
#include "queue"
using namespace std;
int main()
{
int n,k,total=0,t=0;
cin>>k;
while(k--)
{ cin>>n;
if(n==t)
total+=5;
else if(n>t)
total+=(n-t)*6+5;
else total+=(t-n)*4+5;
t=n;
}
cout<<total;
return 0;
}