100903: [AtCoder]ABC090 D - Remainder Reminder

Memory Limit:256 MB Time Limit:2 S
Judge Style:Text Compare Creator:
Submit:0 Solved:0

Description

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

Input

题意翻译

请求出有序正整数对 $(a,b)$ 的个数。每个对需要满足 $1\le a,b\le N$ ,且 $a\bmod b\ge K$ 。 限制:$1\le N\le 10^5,0\le K<N$

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