cf_Divisibility Problem.cpp

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

int main()
{
    int t;

    cin>>t;
    while(t--)
    {   int a,b;
        cin>>a;
        cin>>b;
        if(a%b==0)
            cout<<0<<endl;
        else cout<<((((a/b)+1)*b)-a)<<endl;

    }





}