#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=(int)a;i<(int)b;i++)
#define all(p) p.begin(),p.end()
using ll = long long;
template<class T> bool chmin(T &a, T b){return (a > b ? a = b, 1 : 0);}
template<class T> bool chmax(T &a, T b){return (a < b ? a = b, 1 : 0);}

void solve(){
    const ll lim = (1ll << 30);
    string S;
    ll M;
    cin >> S >> M;
    int N = S.size();
    int len = max(N + 1, 11);
    vector<ll> p(len);
    ll X = 1;
    rep(i, 0, N){
        X *= 10;
        X += S[i] -'0';
        X %= M;
    }
    reverse(all(S));
    rep(i, 0, N){
        p[i] = S[i] - '0';
    }
    p[0]++;
    rep(i, 0, N){
        if (p[i] == 10){
            p[i] = 0;
            p[i + 1]++;
        }
        else break;
    }
    ll ans = (M - X) % M;
    ll rem = 0;
    ll T = 1;
    ll ten = 1, D = 0;
    while (ten <= M) ten *= 10, D++;
    rep(i, 0, len - D + 1){
        ll S = 0;
        for (int j = i + D - 1; j >= i; j--){
            S *= 10;
            S += p[j];
        }
        if (M == S){
            ans = 0;
            break;
        }
        //cout << i << " " << M << " " << S << " " << rem << endl;
        S = (M - S - 1 + ten) % ten;
        chmin(S, lim);
        chmin(ans, rem + S * T + 1);
        rem = max(rem, (9 - p[i]) * T);
        chmin(rem, lim);
        T = min(T * 10, lim);
    }

    p[0] += ans;
    rep(i, 0, len - 1){
        p[i + 1] += p[i] / 10;
        p[i] %= 10;
    }
    while (p.back() == 0) p.pop_back();
    reverse(all(p));
    for (auto x : p) cout << x;
    cout << "\n";
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int t;
    cin >> t;
    while (t--) solve();
}
/*
test
6
7 3
12 3
9 10
249 51
1369 37
2 1
 */