Problem:
Score : 200 points

Problem Statement

Takahashi went to an all-you-can-eat buffet with N kinds of dishes and ate all of them (Dish 1, Dish 2, \ldots, Dish N) once.

The i-th dish (1 \leq i \leq N) he ate was Dish A_i.

When he eats Dish i (1 \leq i \leq N), he gains B_i satisfaction points.

Additionally, when he eats Dish i+1 just after eating Dish i (1 \leq i \leq N - 1), he gains C_i more satisfaction points.

Find the sum of the satisfaction points he gained.

Constraints

All values in input are integers.

2 \leq N \leq 20

1 \leq A_i \leq N

A_1, A_2, ..., A_N are all different.

1 \leq B_i \leq 50

1 \leq C_i \leq 50

Input

Input is given from Standard Input in the following format:

N
A_1 A_2 ... A_N
B_1 B_2 ... B_N
C_1 C_2 ... C_{N-1}

Output

Print the sum of the satisfaction points Takahashi gained, as an integer.

Sample Input 1

3
3 1 2
2 5 4
3 6

Sample Output 1

14

Takahashi gained 14 satisfaction points in total, as follows:

First, he ate Dish 3 and gained 4 satisfaction points.

Next, he ate Dish 1 and gained 2 satisfaction points.

Lastly, he ate Dish 2 and gained 5 + 3 = 8 satisfaction points.

Sample Input 2

4
2 3 4 1
13 5 8 24
45 9 15

Sample Output 2

74

Sample Input 3

2
1 2
50 50
50

Sample Output 3

150

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;

public class Prog
{
    public void run()
    {
        int N = int.Parse(Console.ReadLine());
        var input = Console.ReadLine().Split();
        int[] A = Array.ConvertAll(input, int.Parse);
        input = Console.ReadLine().Split();
        int[] B = Array.ConvertAll(input, int.Parse);
        input = Console.ReadLine().Split();
        int[] C = Array.ConvertAll(input, int.Parse);
        int Old = -5;
        int New = 0;
        int ans = 0;
        for(int i = 0; i < N; i++)
        {
            New = B[A[i] - 1];
            if(Old == A[i] - 1)
            {
                New += C[Old-1];
            }
            Old = A[i];
            ans += New;
        }
        Console.WriteLine(ans);
    }
    public static void Main()
    {
        var prog = new Prog();
        prog.run();
    }
    /*
    最小公倍数
    public static long Lcm(long a, long b)
    {
        return a * b / Gcd(a, b);
    }

    // ユークリッドの互除法 
    public static long Gcd(long a, long b)
    {
        if (a < b)
            // 引数を入替えて自分を呼び出す
            return Gcd(b, a);
        while (b != 0)
        {
            var remainder = a % b;
            a = b;
            b = remainder;
        }
        return a;
    }
    */
    //a<=c, b<=d;
}

//Array.ConvertAll(int.Parse)
//str.IndexOf("Stage",System.StringComparison.CurrentCulture)