#include <bits/stdc++.h>
using namespace std;
int n,d,i,s,sum,k;
int main()
{
	while (~scanf("%d", &n) && n)
	{
		d = 0, sum = 0;
		for (i = 1; i <= n; i++)
		{
		 	cin >> s;
		 	k = s - d;
		 	if (k > 0)
                sum += 6 * k;
		 	else
                sum += -4 * k;
		 	d = s;
		}
		sum += n * 5;
		cout << sum;
	}
	return 0;
}