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);
        long n = sc .nextLong();
        long max = n - 1L;
        long result = 0;

        for (long i = 1L; i < n; i++) {
            long tempMax = max / i;
            result = result + tempMax;
        }

        System.out.println(result);

    }
}
