1008

#include<iostream>
using namespace std;
int main()
{
    int sum = 0;
    int n, a, b;
    a = b = 0;
    cin >> n;
    while (n--)
    {
        cin >> b;
        if (b > a)
        {
            sum += (b - a) * 6;
        }
        else
            sum += (a - b) * 4;
        a = b;
        sum += 5;
    }
    cout << sum << endl;
    system("pause");
    return 0;
}