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 Rust (1.15.1) (judge verdict: Accepted)

use std::str::FromStr;
use std::fmt::Debug;
use std::cmp;

#[allow(dead_code)]
fn read_as_vec<T>() -> Vec<T>
where T: FromStr, <T as FromStr>::Err : Debug{
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();
    s.trim().split_whitespace().map(|c| T::from_str(c).unwrap()).collect()

}

#[allow(dead_code)]
fn read_as_string() -> String{
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();
    s.trim().to_string()
}

struct UnionFind{
    v: Vec<usize>
}

impl UnionFind{
    fn new(n: usize) -> UnionFind{
        let mut v: Vec<usize> = Vec::new();
        for i in 0..n{
         v.push(i);
        }
        UnionFind{v:v}
    }

    fn find(&mut self, i: usize) -> usize{
        if self.v[i] == i{
            i
        }else{
            let ni = self.v[i];
            self.v[i] = self.find(ni);
            self.v[i]
        }
    }

    fn union(&mut self, i: usize, j: usize){
        let root_i = self.find(i);
        let root_j = self.find(j);
        self.v[root_i] = root_j;
    }

}

struct CombMod{
    fac: Vec<u64>,
    inv: Vec<u64>,
    finv: Vec<u64>,
    mmod: u64,
}

impl CombMod{
    pub fn new(max: u64, m: u64) -> CombMod{
        let max: usize = max as usize;
        let mut fac: Vec<u64> = vec![0;max+1];
        let mut finv: Vec<u64> = vec![0;max+1];
        let mut inv: Vec<u64> = vec![0;max+1];

        fac[0] = 1;
        fac[1] = 1;
        finv[0] = 1;
        finv[1] = 1;
        inv[1] = 1;

        for i in 2..max+1{
            fac[i] = fac[i-1] * i as u64 % m;
            inv[i] = m - inv[m as usize %i] * (m/(i as u64)) % m;
            finv[i] = finv[i-1] * inv[i] % m;
        }
        
        CombMod{
            fac: fac,
            finv: finv,
            inv: inv,
            mmod: m,
        }
    }

    fn get(&self, n: u64, m: u64) -> u64{
        assert!(n >= m && n != 0 && m != 0);
        self.fac[n as usize] * self.finv[m as usize] % self.mmod
            * self.finv[(n-m) as usize] % self.mmod
    }
}

fn main(){
    let n: usize = read_as_vec()[0];

    let a: Vec<usize> = read_as_vec();
    let b: Vec<usize> = read_as_vec();
    let c: Vec<usize> = read_as_vec();

    let mut prev_dish = n;
    let mut ans = 0;
    for dish_no in &a{
        if prev_dish + 1 == *dish_no{
            ans += c[prev_dish-1];
        }

        ans += b[*dish_no-1];
        prev_dish = *dish_no;
    }

    println!("{}", ans);
}