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::io::{self, BufRead, Write};

fn solve<R, W>(reader: R, mut writer: W)
where
    R: BufRead,
    W: Write,
{
    let mut lines = reader.lines();
    let _ = lines.next().unwrap().unwrap();
    let line2 = lines.next().unwrap().unwrap();
    let line3 = lines.next().unwrap().unwrap();
    let line4 = lines.next().unwrap().unwrap();

    let a: Vec<i32> = line2.trim().split_whitespace()
        .map(|p| p.parse().unwrap())
        .collect();
    let b: Vec<i32> = line3.trim().split_whitespace()
        .map(|p| p.parse().unwrap())
        .collect();
    let c: Vec<i32> = line4.trim().split_whitespace()
        .map(|p| p.parse().unwrap())
        .collect();

    let mut ans = 0;
    let mut before = -2;
    for i in a {
        ans += b[(i - 1) as usize];
        if i == before + 1 {
            ans += c[(before - 1) as usize];
        }
        before = i;
    }

    writeln!(&mut writer, "{}", ans).unwrap();
}

fn main() {
    let stdio = io::stdin();
    let input = stdio.lock();

    let output = io::stdout();

    solve(input, output);
}

#[cfg(test)]
mod tests {
    use super::*;

    const TESTS: &'static [(&'static [u8], &'static [u8])] = &[
        (
            br"3
3 1 2
2 5 4
3 6", br"14
",
        ),
        (
            br"4
2 3 4 1
13 5 8 24
45 9 15", br"74
",
        ),
        (
            br"2
1 2
50 50
50", br"150
",
        ),
    ];

    #[test]
    fn test_b() {
        for &(input, expected) in TESTS {
            let mut output = Vec::new();
            solve(input, &mut output);
            let expected_str = String::from_utf8(expected.to_vec()).unwrap();
            let output_str = String::from_utf8(output).unwrap();
            assert_eq!(expected_str, output_str);
        }
    }
}