A_Divisibility_Problem.cpp

/*

||-------------------------------||
||      Mohiul Islam Miraz       ||
||-------------------------------||

*/

#include <bits/stdc++.h>
#define swift                     \
    ios_base::sync_with_stdio(0); \
    cin.tie(NULL);
#define sac sort(v.begin(), v.end())
#define sdc sort(v.begin(), v.end(), greater<int>())
#define f1 bool flag = true
#define f0 bool flag = false
#define c0 int count = 0
#define c1 int count = 1
#define s0 long long sum = 0
#define a0 long long ans = 0
#define ll long long
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
#define minus cout << -1 << endl
#define cnt cout << count << endl
#define sm cout << sum << endl
using namespace std;

int main()
{
    swift;
    int t = 1;
    cin >> t;

    while (t--)
    {
        ll a,b; c0;
        int div = 0;
        cin >> a >> b;
        if (a % b == 0)
        {
            cout << 0 << endl;
            continue;
        }

        div = a / b;
        count = (div + 1) * b;
        cout << count - a << endl;
    }
    return 0;
}