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 Kotlin (1.0.0) (judge verdict: Wrong Answer)

fun main(args:Array<String>) {
  val (n, k) = readLine()!!.split(" ").map(String::toInt)
        if(k==0) println(n*n)
        else
        {
    var ans = 0L
                for(i in (k+1..n))
                {
                        ans+=((n/i)*(i-k));
                        if((n%i)>=k)ans+=((n%i)-k+1);
                }
                println(ans)
        }
}