import kotlin.math.sqrt

fun main(args: Array<String>) {
  val n: Int = readLine()!!.toInt()
  val memo: MutableList<Int> = mutableListOf()
  for (i in 1..n - 1) {
    memo.add(calc(i))
  }
  println(memo.sum())
}

fun calc(i: Int): Int {
  var answer = 0
  val n = sqrt(i.toDouble()).toInt()

  for (j in 1..n) {
    if (i % j == 0) {
      answer += 1
    }
  }
  if (i == n * n) {
    answer = answer * 2 - 1
  } else {
    answer = answer * 2
  }
  return answer
}