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.

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.

Constraints

• $1 \leq N \leq 10^5$
• $0 \leq K \leq N-1$
• All input values are integers.

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

见题面 Input 部分

见题面 Output 部分