object Main {
  def main(args: Array[String]): Unit = {
    import scala.io.StdIn.readLine
    val Array(datN) = readLine.split(" ").map(_.toInt)
    //val sqrtN = math.sqrt(datN).toInt
    val datA = for(i <- 1 to datN) yield {
      (datN - 1) / i
    }
    val ans = datA.sum
    println(ans)
  }
}
