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;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            // 各種変数の読み込み
            var n = Readint();
            var a = Readints();
            var b = Readints();
            var c = Readints();
            var bsum = 0;
            for (int i = 0; i < n; i++)
            {
                bsum += b[i];
            }
            for (int i = 1; i < n; i++)
            {
                if (a[i] == a[i-1] + 1)
                {
                    bsum += c[a[i - 1] - 1];
                }
            }
            Console.WriteLine(bsum);

#if DEBUG
            Console.ReadKey();
#endif
        }

        private static int Readint()
        {
            // 1行に1つのintが入力されたのを読む
            return int.Parse(Console.ReadLine());
        }

        private static int[] Readints()
        {
            // 1行に複数のintが入力されたのを読む
            var s = Console.ReadLine().Split(' ');
            var output = new int[s.Length];
            for (int i = 0; i < s.Length; i++)
            {
                output[i] = int.Parse(s[i]);
            }
            return output;
        }

        private static int[][] Readints(int n, bool transpose=false)
        {
            // n行それぞれにintが入力されたのを読む
            // output[行番号][列番号]で返す。
            // transposeがtrueのときは、output[列番号][行番号]で返す。
            var s = Console.ReadLine().Split(' ');
            int rownum = s.Length;
            if (transpose)
            {
                var outputs = new int[rownum][];
                for (int j = 0; j < rownum; j++)
                {
                    outputs[j] = new int[n];
                }
                for (int i = 0; i < s.Length; i++)
                {
                    outputs[i][0] = int.Parse(s[i]);
                }
                for (int l = 1; l < n; l++)
                {
                    var temps = Console.ReadLine().Split(' ');
                    for (int i = 0; i < rownum; i++)
                    {
                        outputs[i][l] = int.Parse(temps[i]);
                    }
                }
                return outputs;
            }
            else
            {
                var outputs = new int[n][];
                outputs[0] = new int[rownum];
                for (int i = 0; i < s.Length; i++)
                {
                    outputs[0][i] = int.Parse(s[i]);
                }
                for (int l = 1; l < n; l++)
                {
                    outputs[l] = new int[rownum];
                    var temps = Console.ReadLine().Split(' ');
                    for (int i = 0; i < rownum; i++)
                    {
                        outputs[l][i] = int.Parse(temps[i]);
                    }
                }
                return outputs;
            }
        }

        private int[] Minusone(int[] x)
        {
            var output = new int[x.Length];
            for (int i = 0; i < x.Length; i++)
            {
                output[i] = x[i] - 1;
            }
            return output;
        }

        // 元の配列をソートして、ソート後の各要素の、元のインデックスを返す
        private static int[] SortwithIndex(double[] data)
        {
            var index = new int[data.Length];
            for (int i = 0; i < data.Length; i++)
            {
                index[i] = i;
            }
            QSort(data, index, 0, data.Length - 1);
            return index;
        }

        private static void QSort(double[] data, int[] index, int low, int high)
        {
            // 要素数が1以下の領域ができた場合、その領域は確定とする。
            if (high - low < 1)
                return;

            // 1. ピボットとして一つ選びそれをPとする。
            var P = data[(low + high + 1) / 2];

            // 2. 左から順に値を調べ、P以上のものを見つけたらその位置をiとする。
            // 3. 右から順に値を調べ、P以下のものを見つけたらその位置をjとする。
            // 4. iがjより左にあるのならばその二つの位置を入れ替え、2に戻る。ただし、次の2での探索はiの一つ右、次の3での探索はjの一つ左から行う。
            int i = low - 1;
            int j = high + 1;
            while (Scan(data, P, ref i, ref j))
            {
                Swap(data, index, i, j);
            }

            // 5. 2に戻らなかった場合、iの左側を境界に分割を行って2つの領域に分け、そのそれぞれに対して再帰的に1からの手順を行う。
            QSort(data, index, low, i - 1);
            QSort(data, index, i, high);
        }

        private static bool Scan(double[] data, double P, ref int i, ref int j)
        {
            while (data[++i] < P) ;
            while (data[--j] > P) ;
            return i < j;
        }
        

        private static void Swap(double[] data, int[] index, int i, int j)
        {
            var temp = data[i];
            data[i] = data[j];
            data[j] = temp;
            var temp2 = index[i];
            index[i] = index[j];
            index[j] = temp2;
        }
    }
}