P2261 [CQOI2007] Remainder Sum

Given positive integers $n$ and $k$, please compute $$G(n, k) = \sum_{i = 1}^n k \bmod i$$ where $k \bmod i$ denotes the remainder when $k$ is divided by $i$.

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

Output one line with one integer representing the answer.

#### 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