import scala.collection.mutable.ListBuffer
import scala.io.StdIn

object Main extends App {

  val l = StdIn.readLine()
  val s1 = StdIn.readLine().split(" ").toString
  val s2 = StdIn.readLine().split(" ").toString

  println(math.abs(impl(s1) - impl(s2)))

  def impl(s: String): Int = {
    val fact0 = 0
    val fact1 = 1
    val fact2 = 1 * 2
    val fact3 = 1 * 2 * 3
    val fact4 = 1 * 2 * 3 * 4
    val fact5 = 1 * 2 * 3 * 4 * 5
    val fact6 = 1 * 2 * 3 * 4 * 5 * 6
    val fact7 = 1 * 2 * 3 * 4 * 5 * 6 * 7
    val fact8 = 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8

    val fact = Array(fact0, fact1, fact2, fact3, fact4, fact5, fact6, fact7, fact8)

    var pendingLen = s.length - 1
    var lowestPending = 1
    val seenSoFar = new ListBuffer[Int]()

    var order = 0

    for (c <- s) {
      val num = c.toString.toInt

      if(num != lowestPending) {
        order += ((num - lowestPending - seenSoFar.count(_ < num)) * fact(pendingLen))
      } else {
        lowestPending += 1
        while (seenSoFar.contains(lowestPending)) {
          lowestPending += 1
        }
      }

      seenSoFar.append(num)
      pendingLen -= 1
    }

    order
  }
}
