CF1409D.Decrease the Sum of Digits

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 $s$ .