object Main extends App {
  val n = readInt
  val as = readLine.split(" ").map(_.toInt)
  val bs = readLine.split(" ").map(_.toInt)
  val cs = readLine.split(" ").map(_.toInt)
  println(bs.sum + (0 to n-2).map(i => if(as(i+1)-as(i)==1) cs(as(i)-1) else 0).sum )
}