#include <bits/stdc++.h>

using namespace std;

constexpr int inf = 1e9;

void fix(string &a) {
    reverse(a.begin(), a.end());
    while (a.size() > 1 && a.back() == '0') {
        a.pop_back();
    }
    reverse(a.begin(), a.end());
}
string add(string a, string b) {
    reverse(a.begin(), a.end());
    reverse(b.begin(), b.end());
    int n = a.size();
    int m = b.size();
    string c(max(n, m), '0');
    int t = 0;
    for (int i = 0; i < max(n, m); i++) {
        int x = (i < n ? a[i] - '0' : 0);
        int y = (i < m ? b[i] - '0' : 0);
        c[i] = char((t + x + y) % 10 + '0');
        t = (t + x + y) / 10;
    }
    if (t) c += char(t + '0');
    reverse(c.begin(), c.end());
    fix(c);
    return c;
}


void solve() {
    string ns;
    int m;
    cin >> ns >> m;
    for (int i = 0; i < 15; i++) ns = '0' + ns;
    string ms = to_string(m);

    int r = 0;
    for (int i = ns.size() - 1; i >= 0; i--) {
        r = (10ll * r + (ns[i] - '0')) % m;
    }
    string ans1 = add(ns, to_string(m - r));
    fix(ans1);
    
    tuple<int, int, int> mx{-1, 0, 0};
    
    for (int i = 0; i + ms.size() - 1 < ns.size(); i++) {
        for (int j = 0; j < ms.size(); j++) {
            if (ns[i] > ms[j]) break;
            if (ns[i] < ms[j]) {
                mx = max(mx, {i + j, -(ms[j] - '0'), i});
                break;
            }
        }
    }
    string ans2 = ns;
    int d = get<2>(mx);
    for (int j = 0; j < ms.size(); j++) {
        ans2[j + d] = ms[j];
    }
    for (int j = ms.size(); j + d < ns.size(); j++) {
        ans2[j + d] = '0';
    }
    fix(ans2);

    string ans;
    if (ans1.size() == ans2.size()) {
        ans = min(ans1, ans2);
    }else {
        ans = (ans1.size() > ans2.size() ? ans2 : ans1);
    }
    cout << ans << '\n';
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int t;
    cin >> t;
    while (t--) {
        solve();
    }
}