1 #include<iostream>
 2 #include<cstdio>
 3 #include<cmath>
 4 #include<cstring>
 5 #define N 100
 6 using namespace std;
 7 int a[N];
 8 int main()
 9 {
10     int n;
11     while(scanf("%d",&n)!=EOF)
12     {
13         if(n==0)
14             break;
15         int sum=n*5;
16         memset(a,0,sizeof(0));
17         int i;
18         for(i=1;i<=n;i++)
19         {
20             scanf("%d",&a[i]);
21         }
22         int j;
23         a[0]=0;
24         for(i=0;i<n;i++)
25         {
26             j=i+1;
27             if(a[j]>a[i])
28                 sum=sum+abs(a[j]-a[i])*6;
29             if(a[j]<a[i])
30                 sum=sum+abs(a[j]-a[i])*4;
31         }
32         printf("%d\n",sum);
33     }
34 }