'use strict'

const main = input => {
	const args = input.split('\n').map(arg => arg.split(' '))
	const N = parseInt(args[0][0], 10)
	const A = args[1].map(arg => parseInt(arg, 10))
	const B = args[2].map(arg => parseInt(arg, 10))
	const C = args[3].map(arg => parseInt(arg, 10))
	let ans = 0
	let prev = -1

	for (let i = 0; i < N; i++) {
		const a = A[i] - 1
		ans += B[a]
		if (prev !== -1 && a === prev + 1) ans += C[prev]
		prev = a
	}

	console.log(ans)
}

main(require('fs').readFileSync('/dev/stdin', 'utf8'))
