Squirrel Liss loves nuts. There are *n* trees (numbered 1 to *n* from west to east) along a street and there is a delicious nut on the top of each tree. The height of the tree *i* is *h*<sub class="lower-index">*i*</sub>. Liss wants to eat all nuts.

Now Liss is on the root of the tree with the number 1. In one second Liss can perform one of the following actions:
 -  Walk up or down one unit on a tree. -  Eat a nut on the top of the current tree. -  Jump to the next tree. In this action the height of Liss doesn't change. More formally, when Liss is at height *h* of the tree *i* (1 ≤ *i* ≤ *n* - 1), she jumps to height *h* of the tree *i* + 1. This action can't be performed if *h* &gt; *h*<sub class="lower-index">*i* + 1</sub>. 
Compute the minimal time (in seconds) required to eat all nuts.
The first line contains an integer *n* (1  ≤  *n* ≤ 10<sup class="upper-index">5</sup>) — the number of trees.

Next *n* lines contains the height of trees: *i*-th line contains an integer *h*<sub class="lower-index">*i*</sub> (1 ≤ *h*<sub class="lower-index">*i*</sub> ≤ 10<sup class="upper-index">4</sup>) — the height of the tree with the number *i*.
t=int(input())
p=0
l=[]
for i in range(t):
    h=int(input())
    if i==0:
       p+=h+1
       l.append(h)
       continue
    try:
        if h<l[i-1] and i!=0:
            p+=(l[i-1]-h)+2
        if h>l[i-1] and i!=0:
            p+=2+(h-l[i-1])
        if h==l[i-1]:
            p+=2
        l.append(h)
    except:
        pass
    
print(p)
    
    
