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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
public class Main {
  	static int mod = 1000000007;
  static int size = 200001;
	static long[] fac = new long[size];
	static long[] finv = new long[size];
	static long[] inv = new long[size];
	static int INF = Integer.MAX_VALUE;
public static void main(String[] args){
	Scanner sc = new Scanner(System.in);
	// 整数の入力
	int N = sc.nextInt();
	int[] A = new int[N];
  int[] B = new int[N];
  int[] C = new int[N-1];
  int i=0;
  int sum=0;
  int befor=-1;
  for(i=0;i<N;i++){
    A[i]=sc.nextInt();
  }
  for(i=0;i<N;i++){
    B[i]=sc.nextInt();
  }
  for(i=0;i<N-1;i++){
    C[i]=sc.nextInt();
  }
  sum=B[A[0]-1];
  for(i=1;i<N;i++){
    sum=sum+B[A[i]-1];
    befor=A[i-1];
    if(befor+1==A[i]){
      sum=sum+C[befor-1];
    }
  }
    System.out.println(sum);



} 

 //fac, inv, finvテーブルの初期化、これ使う場合はinitComb()で初期化必要
	public static  void initComb(){
		fac[0] = finv[0] = inv[0] = fac[1] = finv[1] = inv[1] = 1;
		for (int i = 2; i < size; ++i) {
			fac[i] = fac[i - 1] * i % mod;
			inv[i] = mod - (mod / i) * inv[(int) (mod % i)] % mod;
			finv[i] = finv[i - 1] * inv[i] % mod;
		}
	}
 
	//nCk % mod
	public static long comb(int n, int k){
        if (n < k) return 0;
        if (n < 0 || k < 0) return 0;
		return fac[n] * finv[k] % mod * finv[n - k] % mod;
	}
 
	//n! % mod
	public static long fact(int n){
		return fac[n];
	}
 
	//(n!)^-1 with % mod
	public static long finv(int n){
		return finv[n];
	}
  
}