#include <bits/stdc++.h>

#define ll long long
#define ul unsigned long long
#define ld long double
#define vll(v) vector<ll>v
//#define vll(v,n) vector<ll>v(n);
#define mll(m) map<ll,ll>m;
#define sll(s) set<ll>s;
#define iv(v) for(auto &i:v) cin >> i;
#define ov(v) for(auto &i:v) cout << i << " ";
#define Bismillah ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);

using namespace std;

string toBin(ll n) {
    string s;
    while (n) {
        s.push_back(n%2+'0');
        n/=2;
    }
    reverse(s.begin(), s.end());
    return s;
}

void solve() {
    string s;
    ll k;
    cin >> s >> k;
    k--;
    string b=toBin(k);
    string a;
    sort(s.begin(), s.end());
    for (int i=b.length()-1, j=0; i>=0; i--, j++) {
        if (b[i]-'0') {
            a.push_back(s[j]);
        }
    }
    cout << a << endl;
}

int main() {
    Bismillah
    ll t=1;
    cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}