/*
	水题：模拟
	一开始把意思读错了！！
	The numbers denote at which floors the elevator will stop, in specified order.
	少读了in specified order！导致自己用排序求其最值！
	
	题意：
		n个整数，后一个若比前一个大，ans+=差值*6
			否则ans+=差值*4
		ans+=5意为在每个整数点停留5秒 
*/

#include <iostream>
#include <algorithm>
#include <stdio.h>
#include <math.h>
#include <vector>
#include <string>
#include <cstring>
#include <sstream>
using namespace std;

#define For1(i,a,b) for (i=a;i<b;i++)
#define For2(i,a,b) for (i=a;i<=b;i++)
#define Dec(i,a,b) for (i=a;i>b;i--)
#define Dec2(i,a,b) for (i=a;i>=b;i--)
#define Sca(x) scanf("%d",&x)
#define Fill(x,a) memset(x,a,sizeof(x))
#define MAXN 0x7fffffff

int main()
{
	int n,m,now,i,ans,before;
	while(cin>>n)
	{
		if (!n) break;
		ans=now=before=0;
		For2(i,1,n)
		{
			Sca(now);
			if (now>before) ans+=6*(now-before);
			else ans+=4*(before-now);
			ans+=5;
			before=now;
		}
		cout<<ans<<endl;
	}
	return 0;
}