#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(x) ::begin(x), ::end(x)
void _d(auto... x) { ((cerr << ' ' << x), ...) << endl; }
#define debug(x...) cerr << "["#x"]:", _d(x)

int main() {
    cin.tie(0)->sync_with_stdio(0);

    int T;
    cin >> T;
    while (T--) {
        string a;
        ll m;
        cin >> a >> m;
        string b = to_string(m);
        a = string(100, '0') + a;

        ll rest = 0;
        for (char c : a | views::reverse) {
            rest = (rest*10 + c-'0') % m;
        }
        rest = m - rest;
        ll ans = rest;

        auto add = [&](ll x) {
            ans -= x;
            string y = to_string(x);
            reverse(all(a));
            reverse(all(y));
            ll carry = 0;
            for (int i=0; i<ssize(y) || carry > 0; i++) {
                if (i < ssize(y)) carry += y[i] - '0';
                if (i == ssize(a)) a.push_back('0' + (carry % 10));
                else {
                    carry += a[i] - '0';
                    a[i] = '0' + (carry % 10);
                }
                carry /= 10;
            }
            reverse(all(a));
        };
        add(1);

        ll idk = 1;
        for (int it=0; it<15; it++, idk *= 10) {
            for (int i=0; i+ssize(b)<=ssize(a); i++) {
                if (a.substr(i, ssize(b)) == b) ans = 0;
            }
            ll x = stoll(a.substr(ssize(a)-ssize(b)-it, ssize(b)));
            if (x <= m) {
                ans = min<__int128>(ans, (__int128)(m-x)*idk);
            }
            if (a[ssize(a)-1-it] != '0') {
                x = ('9' - a[ssize(a)-1-it] + 1) * idk;
                if (x < ans) add(x);
                else break;
            }
        }

        add(ans);
        int zero = 0;
        while (a[zero] == '0') zero++;
        a = a.substr(zero);
        cout << a << '\n';
    }
}