#include<iostream>
using namespace std;
int main(){
int a,t;int time;
int sub ;
while(cin>>t){
if(t==0)break;
time = 0;
sub = 0;
for(int i=1;i<=t;i++){
cin>>a;
if(a>sub)
time+=(a-sub)*6;
else
time+=(sub-a)*4;
time+=5;
sub = a;
}
cout<<time<<endl;
}
return 0;
}