import java.util.*

fun main(args: Array<String>) {
    val sc = Scanner(System.`in`)
    val n = sc.nextInt()
    val a = (1..n).map { sc.nextInt() - 1 }
    val b = (1..n).map { sc.nextInt() }
    val c = (1 until n).map { sc.nextInt() }
    var ans = 0
    repeat(n) {
        ans += b[a[it]]
        if (0 < it && a[it] == a[it - 1] + 1) {
            ans += c[a[it - 1]]
        }
    }
    println(ans)
}