杭电1008

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