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 Haskell (GHC 7.10.3) (judge verdict: Accepted)

import Data.List
import Control.Monad
import qualified Data.Vector.Unboxed as V
import qualified Data.ByteString.Char8 as BS

getIntList :: IO [Int]
getIntList = unfoldr (BS.readInt . BS.dropWhile (== ' ')) <$> BS.getLine

mod' :: Integral a => a -> a
mod' n = if n < 1000000007 then n else n `mod` 1000000007

f :: V.Vector Int -> [Int] -> Int
f cs (a:aa:as) = if (a+1) == aa then (cs V.! (a-1)) + (f cs (aa:as)) else f cs (aa:as)
f _ _ = 0

main :: IO ()
main = do
  n <- readLn :: IO Int
  as <- getIntList
  bs <- getIntList
  cs <- V.fromList <$> getIntList
  print $ (f cs as) + (sum bs)