PAT 甲级1008【1008 Elevator】

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StreamTokenizer;

public class Main {
    @SuppressWarnings("unchecked")
    public static void main(String[] args) throws IOException {
        StreamTokenizer in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
        in.nextToken();
        int n = (int) in.nval;
        int last = 0;
        int sum = 0;
        for (int i = 0; i < n; i++) {
            in.nextToken();
            int next = (int) in.nval;
            if (next > last) {
                sum += 6 * (next - last);
                sum += 5;
                last = next;
            } else {
                sum += 4*(last - next);
                sum += 5;
                last = next;
            }
        }
        System.out.println(sum);
    }
}