// Online C++ compiler to run C++ program online

include <bits/stdc++.h>

using namespace std;

int main() { int test; cin>>test; while(test--){ string a,b; int j=0; unordered_map<char,int> sol; cin>>a; cin>>b; for(auto i: a){ sol[i] = 0; } for(auto i: b){ sol[i]++; } for(auto i: a){ while(a[i]){ b[j] = i; j++; a[i]--; } } }

return 0;

}