Decrease the Sum of Digits

题意翻译

给定一个数 $n$，将 $n$ 加上一个数 $k$，使得和的**数码**和不大于 $s$，求 $k$ 的最小值。 输入包含多组数据。

题目描述

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.

输入输出格式

输入格式

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 $ ).

输出格式

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 $ .

输入输出样例

输入样例 #1

5
2 1
1 1
500 4
217871987498122 10
100000000000000001 1

输出样例 #1

8
0
500
2128012501878
899999999999999999