13351335 SUSTech Online Judge
Problem 1335 --Sum of Digits

## 1335: Sum of Digits

Time Limit: 1 Sec  Memory Limit: 128 MB
Submit: 1028  Solved: 219
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## Description

Pisces has a positive integer $$n$$. In one operation, Pisces can increase $$n$$ by one (that is to say, make $$n=n+1$$). Pisces wants to know the minimum number of operations to make the sum of digits of $$n$$ be no more than a given number $$s$$.

## Input

The first line of the input contains one integer $$t(1\leq t\leq 2*10^4)$$ — the number of test cases. Then $$t$$ test cases follow.

The only line of the test case contains two integers $$n$$ and $$s(1\leq n\leq 10^{18},1\leq s\leq 162)$$.

## Output

For each test case, print the answer.

## Sample Input

5
2 1
1 1
500 4
217871987498122 10
100000000000000001 1


## Sample Output

8
0
500
2128012501878
899999999999999999


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