A13283. Divisibility Problem

You are given two positive integers $a$ and $b$ . In one move you can increase $a$ by $1$ (replace $a$ with $a+1$ ). Your task is to find the minimum number of moves you need to do in order to make $a$ divisible by $b$ . It is possible, that you have to make $0$ moves, as $a$ is already divisible by $b$ . You have to answer $t$ independent test cases.

The first line of the input contains one integer $t$ ( $1 \le t \le 10^4$ ) — the number of test cases. Then $t$ test cases follow.

The only line of the test case contains two integers $a$ and $b$ ( $1 \le a, b \le 10^9$ ).

For each test case print the answer — the minimum number of moves you need to do in order to make $a$ divisible by $b$ .