#include <bits/stdc++.h>

using namespace std;

int m;

string N, M;

void print(string str) { for (int i = 0; i < str.size(); ++i) cout << (char)(str[i] + '0'); cout << endl; }

string add(string N, int x) {
    reverse(N.begin(), N.end());
    vector<int> res;
    for (int i = 0; i < N.size(); ++i) res.push_back(N[i]);
    res[0] += x;
    for (int i = 0; i < res.size(); ++i) {
        if (res[i] >= 10) {
            if (i + 1 == res.size()) res.push_back(res[i] / 10);
            else res[i + 1] += res[i] / 10;
            res[i] %= 10;
        }
    }
    reverse(res.begin(), res.end());
    N = "";
    for (int i = 0; i < res.size(); ++i) N.push_back(res[i]);
    return N;
}

string solve1(){
    ll r = 0;
    for (int i = 0; i < N.size(); ++i) {
        r = (r * 10 + N[i]) % m;
    }
    return add(N, m - r);
}

bool check1(int l){
    if (l < 0) return false;
    for (int i = 0; i < M.size(); ++i) if (M[i] != N[l + i]) return false;
    return true;
}

bool check2(int l, int d) {
    if (l < 0) return false;
    for (int i = 0; i + 1 < M.size(); ++i) if (M[i] != N[l + i]) return false;
    if (d != M.back()) return false;
    return true;
}

string solve2(){
    M = "";
    for (int x = m; x; x/= 10) M += (x % 10);
    reverse(M.begin(), M.end());
    if (N.size() < M.size()) {
        return M;
    }
    string res = N;
    vector<bool> f(N.size(), 0);
    for (int i = 0; i < N.size(); ++i) {
        f[i] = (i ? f[i - 1] : 0) | check1(i - (int)M.size() + 1);
    }
    for (int i = (int)N.size() - 1; i >= 0; --i) {
        for (int d = N[i] + 1; d < 10; ++d) {
            if ((i && f[i - 1]) || check2(i - (int)M.size() + 1, d)) {
                res[i] = d;
                for (int k = i + 1; k < res.size(); ++k) res[k] = 0;
                return res;
            }
            if (i + M.size() < N.size()) {
                res[i] = d;
                for (int k = i + 1; k < N.size() - M.size(); ++k) res[k] = 0;
                for (int k = N.size() - M.size(); k < N.size(); ++k) res[k] = M[k - (N.size() - M.size())];
                return res;
            }
        }
    }
    return "";
}

string chkmin(string ans1, string ans2) {
    if (ans1 == "") return ans2;
    if (ans2 == "") return ans1;
    if (ans1.size() < ans2.size()) return ans1;
    if (ans2.size() < ans1.size()) return ans2;
    for (int i = 0; i < ans1.size(); ++i) {
        if (ans1[i] < ans2[i]) return ans1;
        if (ans2[i] < ans1[i]) return ans2;
    }
    return ans1;
}

string solve3(){
    string ret = "";
    for (int i = (int)N.size() - (int)M.size(); i >= 0 && i >= (int)N.size() - (int)M.size() * 2; --i) {
        int p = i;
        string res = N;
        bool ok = true, flg = false;
        for (int j = 0; j < M.size(); ++j, ++p) {
            if (!flg && M[j] < N[p]) {
                ok = false;
                break;
            }
            res[p] = M[j];
            if (res[p] > N[p]) flg = true;
        }
        // cout << i << " "; print(res); cout << " ok = " << ok << " " << flg << endl;
        if (ok && flg) {
            for (; p < res.size(); ++p) res[p] = 0;
            ret = chkmin(ret, res);
        }
    }
    return ret;
}

inline void solve(){
    cin >> N >> m;
    for (int i = 0; i < N.size(); ++i) N[i] -= '0';
    string ans1 = solve1();
    string ans2 = solve2();
    string ans3 = solve3();
    print(chkmin(ans3, chkmin(ans1, ans2)));
}

int main(){
    int T;
    for (cin >> T; T--; solve());
    return 0;
}

answer.code: In function ‘std::string solve1()’:
answer.code:30:5: error: ‘ll’ was not declared in this scope
   30 |     ll r = 0;
      |     ^~
answer.code:32:9: error: ‘r’ was not declared in this scope
   32 |         r = (r * 10 + N[i]) % m;
      |         ^
answer.code:34:23: error: ‘r’ was not declared in this scope
   34 |     return add(N, m - r);
      |                       ^