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 Go (1.6) (judge verdict: Wrong Answer)

package main
import "fmt"
func main() {
  var n,k int
  var m int64
  fmt.Scan(&n,&k)
  for b:=k+1;b<n+1;b++ {
    for r:=k;r<b;r++ {
      m += int64((n-r+b-1)/b)
    }
  }
  fmt.Println(m)
}