学步园

#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;
}