Problem:
Score : 400 points

Problem Statement

Takahashi had a pair of two positive integers not exceeding N, (a,b), which he has forgotten.
He remembers that the remainder of a divided by b was greater than or equal to K.
Find the number of possible pairs that he may have had.

Constraints

1 \leq N \leq 10^5

0 \leq K \leq N-1

All input values are integers.

Input

Input is given from Standard Input in the following format:

N K

Output

Print the number of possible pairs that he may have had.

Sample Input 1

5 2

Sample Output 1

7

There are seven possible pairs: (2,3),(5,3),(2,4),(3,4),(2,5),(3,5) and (4,5).

Sample Input 2

10 0

Sample Output 2

100

Sample Input 3

31415 9265

Sample Output 3

287927211

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Time Limit Exceeded)

import java.io.*;

public class Main{
  public static void main(String[] args) {
    try {
      BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
      int n, k, ind, i, j, count = 0;
      String str;

      str = reader.readLine();
      ind = str.indexOf(" ");
      n = Integer.parseInt(str.substring(0, ind));
      k = Integer.parseInt(str.substring(ind+1));

      for(i = 1; i <= n; i++ ){
        for(j = 1; j<= n; j++){
          if(i%j >= k){
            count = ++count;
          }
        }
      }

      System.out.println(count);
      
    }
    catch (Exception e) {
      
    }
  }
}