Problem:
Score : 300 points

Problem Statement

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.

Sample Input 1

3

Sample Output 1

3

There are 3 tuples of integers that satisfy A \times B + C = 3: (A, B, C) = (1, 1, 2), (1, 2, 1), (2, 1, 1).

Sample Input 2

100

Sample Output 2

473

Sample Input 3

1000000

Sample Output 3

13969985

Solution in Java (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
import java.lang.*;
import java.io.*;

public class Main {
    public static void main(String[] args) {
     Scanner sc=new Scanner(System.in);
     if(sc.hasNextInt()) 
      {
          int n=sc.nextInt();
          deployC obj=new deployC();
          obj.solve(n);
      }
        
  }
    
}
class deployC
{
    public void solve(int n)
    {
        int ans=0;
        for(int fir=1;fir<Math.sqrt(n-1);fir++)
        {
            for(int sec=fir;sec*fir<=n-1;sec++)
            {
                ans++;
            }
        }
        ans=ans*2;
        ans=ans-(int)Math.sqrt(n-1);
        System.out.println(ans);
    }
    
}