题目描述

Given a positive integer $x$, find the minimum positive integer $y$ such that the number of $\textbf{carries}^1$ of $x+y$ is exactly $k$.

We adds numbers $\textbf{by column addition in base-ten}$, just like what we normally do in primary school. For example, there are two carries in the following addition.

$^1$ which means 进位 in Chinese.

输入格式

The first line contains an integer $T$ $(1\leq T\leq 10^5)$ $-$ the number of test cases.

For each test case, the first line contains two integers $x, k$ $(1\leq x < 10^{18}, 0\leq k \leq 18)$.

输出格式

For each test case, output one integer representing the answer in one line. If there is no solution, output $-1$ instead.

4
12345678 0
12345678 5
12345678 18
990099 5

1
54322
999999999987654322
9910