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D - Remainder Reminder

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.

5 2

7

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

10 0

100

31415 9265

287927211