1328A.cpp

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.

#Input
The first line of the input contains one integer t (1≤t≤104) — the number of test cases. Then t test cases follow.

The only line of the test case contains two integers a and b (1≤a,b≤109).

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

#CODE:
#include<bits/stdc++.h>
using namespace std;

int main()
{
	int n;
	cin>>n;
	while(n--)
	{
		int a , b;
		cin>>a>>b;
		int c = a/b;
		int d = c+1;
		int e = a%b;
		if(e==0)
		cout<<e<<endl;
		else
		{
		int f = d*b;
		int g = f-a;
		cout<<g<<endl;
		}
	}
	return 0;
}