import java.util.*

fun main(args: Array<String>) {
    val scanner = Scanner(System.`in`)
    val n = scanner.nextInt()
    val a = IntArray(n) { scanner.nextInt() - 1 }
    val b = IntArray(n) { scanner.nextInt() }
    val c = IntArray(n - 1) { scanner.nextInt() }


    val ret =
        b[a[0]] + (1 until n).map { i ->
            val cp = if (a[i - 1] + 1 == a[i]) c[a[i - 1]] else 0
            b[a[i]] + cp
        }.sum()

    println(ret)
}