Given is a positive integer N. How many tuples (A,B,C) of positive integers satisfy A \times B + C = N?

Constraints

* 2 \leq N \leq 10^6
* All values in input are integers.

Input

Input is given from Standard Input in the following format:


N


Output

Print the answer.

Examples

Input

3


Output

3


Input

100


Output

473


Input

1000000


Output

13969985
import java.util.Scanner;

public class Main {

  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    int ans = 0;
    int[] a = new int[n + 1];

    for (int i = 1; i < n; i++) {
      for (int j = 1; (i * j) < n; j++) {
        a[i * j]++;
      }
    }

    for (int i = 1; i <= n; i++) {
      ans += a[i];
    }

    System.out.println(ans);

  }
}