Decrease the Sum of Digits
Description
You are given a positive integer $n$. In one move, you can increase $n$ by one (i.e. make $n := n + 1$). Your task is to find the minimum number of moves you need to perform in order to make the sum of digits of $n$ be less than or equal to $s$.
You have to answer $t$ independent test cases.
The first line of the input contains one integer $t$ ($1 \le t \le 2 \cdot 10^4$) — the number of test cases. Then $t$ test cases follow.
The only line of the test case contains two integers $n$ and $s$ ($1 \le n \le 10^{18}$; $1 \le s \le 162$).
For each test case, print the answer: the minimum number of moves you need to perform in order to make the sum of digits of $n$ be less than or equal to $s$.
Input
The first line of the input contains one integer $t$ ($1 \le t \le 2 \cdot 10^4$) — the number of test cases. Then $t$ test cases follow.
The only line of the test case contains two integers $n$ and $s$ ($1 \le n \le 10^{18}$; $1 \le s \le 162$).
Output
For each test case, print the answer: the minimum number of moves you need to perform in order to make the sum of digits of $n$ be less than or equal to $s$.
Samples
5
2 1
1 1
500 4
217871987498122 10
100000000000000001 1
8
0
500
2128012501878
899999999999999999