Problem Description

Given positive integers $n$ and $k$, please compute

where $k \bmod i$ denotes the remainder when $k$ is divided by $i$.

Input Format

The input contains a single line with two integers, $n$ and $k$.

Output Format

Output one line with one integer representing the answer.

10 5

29

Hint

Sample 1 Explanation

$G(10, 5) = 0 + 1 + 2 + 1 + 0 + 5 + 5 + 5 + 5 + 5 = 29$.

Constraints

• For 30% of the testdata, it is guaranteed that $n, k \leq 10^3$.
• For 60% of the testdata, it is guaranteed that $n, k \leq 10^6$.
• For 100% of the testdata, it is guaranteed that $1 \leq n, k \leq 10^9$.

Added a set of hack testdata on 2024/2/13.

Translated by ChatGPT 5