| Sparkle gives you two arrays $a$ and $b$ of length $n$. Initially, your score is $0$. In one operation, you can choose an integer $i$ and add $a_i$ to your score. Then, you must set $a_i$ = $\max(0, a_i - b_i)$. | |
| You only have time to perform $k$ operations before Sparkle sets off a nuclear bomb! What is the maximum score you can acquire after $k$ operations? | |
| The first line contains $t$ ($1 \leq t \leq 1000$) — the number of test cases. | |
| The first line of each test case contains $n$ and $k$ ($1 \leq n \leq 2 \cdot 10^5, 1 \leq k \leq 10^9$) — the length of the arrays and the number of operations you can perform. | |
| The following line contains $n$ integers $a_1, a_2, ... a_n$ ($1 \leq a_i \leq 10^9$). | |
| The following line contains $n$ integers $b_1, b_2, ... b_n$ ($1 \leq b_i \leq 10^9$). | |
| It is guaranteed that the sum of $n$ for all test cases does not exceed $2 \cdot 10^5$. | |
| For each test case, output an integer, the maximum score you can acquire after $k$ operations. | |